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           The  following types of expansions are performed in the indicated order
           in five steps:
           History Expansion
                  This is performed only in interactive shells.
           Alias Expansion
                  Aliases are expanded immediately  before  the  command  line  is
                  parsed as explained under Aliasing in zshmisc(1).
           Process Substitution
           Parameter Expansion
           Command Substitution
           Arithmetic Expansion
           Brace Expansion
                  These  five  are performed in one step in left-to-right fashion.
                  After these expansions, all unquoted occurrences of the  charac-
                  ters '\', ''' and '"' are removed.
           Filename Expansion
                  If  the  SH_FILE_EXPANSION option is set, the order of expansion
                  is modified for compatibility with sh and  ksh.   In  that  case
                  filename  expansion  is performed immediately after alias expan-
                  sion, preceding the set of five expansions mentioned above.
           Filename Generation
                  This expansion, commonly referred to as globbing, is always done
           The following sections explain the types of expansion in detail.


           History  expansion  allows you to use words from previous command lines
           in the command line you are typing.  This simplifies  spelling  correc-
           tions and the repetition of complicated commands or arguments.  Immedi-
           ately before execution, each command is saved in the history list,  the
           size  of  which  is controlled by the HISTSIZE parameter.  The one most
           recent command is always retained in any case.  Each saved  command  in
           the  history  list  is called a history event and is assigned a number,
           beginning with 1 (one) when the shell starts up.   The  history  number
           that  you  may see in your prompt (see EXPANSION OF PROMPT SEQUENCES in
           zshmisc(1)) is the number that is to be assigned to the next command.
           A history expansion begins with the first character  of  the  histchars
           parameter,  which is '!' by default, and may occur anywhere on the com-
           mand line; history expansions do not nest.  The '!' can be escaped with
           '\' or can be enclosed between a pair of single quotes ('') to suppress
           its special meaning.  Double quotes will not work for this.   Following
           every  history  reference  with no event specification always refers to
           the previous command.
           For example, '!' is the event designator for the previous  command,  so
           '!!:1'  always  refers  to  the first word of the previous command, and
           '!!$' always refers to the last word of  the  previous  command.   With
           CSH_JUNKIE_HISTORY set, then '!:1' and '!$' function in the same manner
           as '!!:1' and '!!$', respectively.  Conversely,  if  CSH_JUNKIE_HISTORY
           is  unset,  then  '!:1'  and  '!$'  refer  to the first and last words,
           respectively, of the same event referenced by the nearest other history
           reference  preceding them on the current command line, or to the previ-
           ous command if there is no preceding reference.
           The character sequence '^foo^bar' (where '^'  is  actually  the  second
           character of the histchars parameter) repeats the last command, replac-
           ing the string foo with bar.  More precisely, the sequence  '^foo^bar^'
           is synonymous with '!!:s^foo^bar^', hence other modifiers (see the sec-
           tion  'Modifiers')  may  follow  the   final   '^'.    In   particular,
           '^foo^bar^:G' performs a global substitution.
           If  the  shell encounters the character sequence '!"' in the input, the
           history mechanism is temporarily disabled until the current  list  (see
           zshmisc(1))  is  fully parsed.  The '!"' is removed from the input, and
           any subsequent '!' characters have no special significance.
           A less convenient but more comprehensible form of command history  sup-
           port is provided by the fc builtin.
       Event Designators
           An  event designator is a reference to a command-line entry in the his-
           tory list.  In the list below, remember that the initial  '!'  in  each
           item  may  be  changed  to  another  character by setting the histchars
           !      Start a history expansion, except when followed by a blank, new-
                  line,  '=' or '('.  If followed immediately by a word designator
                  (see the section 'Word Designators'), this forms a history  ref-
                  erence with no event designator (see the section 'Overview').
           !!     Refer  to  the  previous  command.   By  itself,  this expansion
                  repeats the previous command.
           !n     Refer to command-line n.
           !-n    Refer to the current command-line minus n.
           !str   Refer to the most recent command starting with str.
                  Refer to the most recent command containing str.   The  trailing
                  '?'  is necessary if this reference is to be followed by a modi-
                  fier or followed by any text that is not to be  considered  part
           designators include:
           0      The first input word (command).
           n      The nth argument.
           ^      The first argument.  That is, 1.
           $      The last argument.
           %      The word matched by (the most recent) ?str search.
           x-y    A range of words; x defaults to 0.
           *      All the arguments, or a null value if there are none.
           x*     Abbreviates 'x-$'.
           x-     Like 'x*' but omitting word $.
           Note that a '%' word designator works only when used in  one  of  '!%',
           '!:%'  or '!?str?:%', and only when used after a !? expansion (possibly
           in an earlier command).  Anything else results in  an  error,  although
           the error may not be the most obvious one.
           After  the  optional  word designator, you can add a sequence of one or
           more of the following modifiers, each preceded by a ':'.   These  modi-
           fiers  also  work  on  the  result of filename generation and parameter
           expansion, except where noted.
           a      Turn a file name into an absolute path:   prepends  the  current
                  directory, if necessary, and resolves any use of '..' and '.' in
                  the path.  Note that the transformation takes place even if  the
                  file or any intervening directories do not exist.
           A      As  'a',  but also resolve use of symbolic links where possible.
                  Note that resolution of '..' occurs before  resolution  of  sym-
                  bolic  links.   This  call is equivalent to a unless your system
                  has the realpath system call (modern systems do).
           c      Resolve a command name into an absolute path  by  searching  the
                  command path given by the PATH variable.  This does not work for
                  commands containing directory parts.  Note also that  this  does
                  not  usually  work as a glob qualifier unless a file of the same
                  name is found in the current directory.
           e      Remove all but the part of the filename extension following  the
                  '.';  see  the  definition  of  the  filename  extension  in the
                  description of the r modifier below.   Note  that  according  to
                  that definition the result will be empty if the string ends with
                  a '.'.
           h      Remove a trailing pathname component, leaving  the  head.   This
                  works like 'dirname'.
           l      Convert the words to all lowercase.
           p      Print  the  new  command but do not execute it.  Only works with
                  history expansion.
                  Substitute r for l as described below.  The substitution is done
                  only  for  the  first string that matches l.  For arrays and for
                  filename generation, this applies to each word of  the  expanded
                  text.  See below for further notes on substitutions.
                  The  forms  'gs/l/r' and 's/l/r/:G' perform global substitution,
                  i.e. substitute every occurrence of r for l.  Note that the g or
                  :G must appear in exactly the position shown.
                  See further notes on this form of substitution below.
           &      Repeat  the  previous  s  substitution.  Like s, may be preceded
                  immediately by a g.  In parameter expansion the  &  must  appear
                  inside braces, and in filename generation it must be quoted with
                  a backslash.
           t      Remove all leading pathname components, leaving the tail.   This
                  works like 'basename'.
           u      Convert the words to all uppercase.
           x      Like  q, but break into words at whitespace.  Does not work with
                  parameter expansion.
           The s/l/r/ substitution works as follows.   By  default  the  left-hand
           side  of  substitutions  are  not patterns, but character strings.  Any
           character can be used as the delimiter in place of  '/'.   A  backslash
           quotes   the   delimiter   character.    The   character  '&',  in  the
           right-hand-side r, is replaced by the text from the  left-hand-side  l.
           The  '&'  can  be  quoted with a backslash.  A null l uses the previous
           string either from the previous l or from the contextual scan string  s
           from  '!?s'.  You can omit the rightmost delimiter if a newline immedi-
           ately follows r; the rightmost '?' in a context scan can  similarly  be
           omitted.  Note the same record of the last l and r is maintained across
           all forms of expansion.
           Note that if a '&' is used within glob qualifers an extra backslash  is
           needed as a & is a special character in this case.
           If  the  option HIST_SUBST_PATTERN is set, l is treated as a pattern of
           the usual form described in  the  section  FILENAME  GENERATION  below.
           This can be used in all the places where modifiers are available; note,
           however, that in globbing qualifiers parameter substitution has already
           taken  place,  so parameters in the replacement string should be quoted
           to ensure they are replaced at the correct time.  Note also  that  com-
           plicated  patterns  used  in  globbing qualifiers may need the extended
           glob qualifier notation (#q:s/.../.../) in order for the shell to  rec-
           ognize the expression as a glob qualifier.  Further, note that bad pat-
           terns in the substitution are not subject to the NO_BAD_PATTERN  option
           so will cause an error.
           to the start and end of each word (#%).  This turns  on  backreferences
           ((#b)),  so  that  the  parenthesised subexpression is available in the
           replacement string as ${match[1]}.  The replacement string is quoted so
           that the parameter is not substituted before the start of filename gen-
           The following f, F, w and W modifiers work only with  parameter  expan-
           sion and filename generation.  They are listed here to provide a single
           point of reference for all modifiers.
           f      Repeats the immediately (without  a  colon)  following  modifier
                  until the resulting word doesn't change any more.
                  Like  f,  but repeats only n times if the expression expr evalu-
                  ates to n.  Any character can be used instead  of  the  ':';  if
                  '(',  '[',  or '{' is used as the opening delimiter, the closing
                  delimiter should be ')', ']', or '}', respectively.
           w      Makes the immediately following modifier work on  each  word  in
                  the string.
           W:sep: Like  w  but  words are considered to be the parts of the string
                  that are separated by sep. Any character can be used instead  of
                  the ':'; opening parentheses are handled specially, see above.


           Each  part  of  a  command  argument  that  takes  the  form '<(list)',
           '>(list)' or '=(list)' is subject to process substitution.  The expres-
           sion  may be preceded or followed by other strings except that, to pre-
           vent clashes with commonly occurring strings  and  patterns,  the  last
           form  must  occur at the start of a command argument, and the forms are
           only expanded when first parsing command or assignment arguments.  Pro-
           cess substitutions may be used following redirection operators; in this
           case, the substitution must appear with no trailing string.
           In the case of the < or > forms, the shell runs the commands in list as
           a  subprocess of the job executing the shell command line.  If the sys-
           tem supports the /dev/fd mechanism, the command argument is the name of
           the  device  file corresponding to a file descriptor; otherwise, if the
           system supports named pipes (FIFOs), the command  argument  will  be  a
           named  pipe.   If the form with > is selected then writing on this spe-
           cial file will provide input for list.  If < is  used,  then  the  file
           passed  as an argument will be connected to the output of the list pro-
           cess.  For example,
                  paste <(cut -f1 file1) <(cut -f3 file2) |
                  tee >(process1) >(process2) >/dev/null
           cuts fields 1 and 3 from the files file1 and file2 respectively, pastes
           the  results  together, and sends it to the processes process1 and pro-
           The = form is useful as both the /dev/fd and the named pipe implementa-
           tion of <(...) have drawbacks.  In the former case, some programmes may
           automatically  close  the  file descriptor in question before examining
           the file on the command line, particularly if  this  is  necessary  for
           security  reasons such as when the programme is running setuid.  In the
           second case, if the programme does not actually open the file, the sub-
           shell  attempting  to read from or write to the pipe will (in a typical
           implementation,  different  operating  systems   may   have   different
           behaviour)  block  for  ever and have to be killed explicitly.  In both
           cases, the shell actually supplies the information  using  a  pipe,  so
           that  programmes  that  expect to lseek (see lseek(2)) on the file will
           not work.
           Also note that the previous example can be  more  compactly  and  effi-
           ciently written (provided the MULTIOS option is set) as:
                  paste <(cut -f1 file1) <(cut -f3 file2) \
                  > >(process1) > >(process2)
           The  shell uses pipes instead of FIFOs to implement the latter two pro-
           cess substitutions in the above example.
           There is an additional problem with >(process); when this  is  attached
           to  an  external command, the parent shell does not wait for process to
           finish and hence an immediately following command cannot  rely  on  the
           results  being  complete.   The  problem  and  solution are the same as
           described in the section MULTIOS in zshmisc(1).  Hence in a  simplified
           version of the example above:
                  paste <(cut -f1 file1) <(cut -f3 file2) > >(process)
           (note that no MULTIOS are involved), process will be run asynchronously
           as far as the parent shell is concerned.  The workaround is:
                  { paste <(cut -f1 file1) <(cut -f3 file2) } > >(process)
           The extra processes here are spawned from the parent shell  which  will
           wait for their completion.
           Another problem arises any time a job with a substitution that requires
           a temporary file is disowned by the shell,  including  the  case  where
           '&!'  or '&|' appears at the end of a command containing a subsitution.
           In that case the temporary file will not be cleaned up as the shell  no
           longer  has  any memory of the job.  A workaround is to use a subshell,
           for example,
                  (mycmd =(myoutput)) &!
           as the forked subshell will wait for the command to finish then  remove
           the temporary file.
           parameter expansion, command substitution,  and  arithmetic  expansion.
           In  addition to the following operations, the colon modifiers described
           in the section 'Modifiers' in the section 'History  Expansion'  can  be
           applied:   for example, ${i:s/foo/bar/} performs string substitution on
           the expansion of parameter $i.
                  The value, if any, of the parameter name  is  substituted.   The
                  braces are required if the expansion is to be followed by a let-
                  ter, digit, or underscore that is not to be interpreted as  part
                  of  name.   In  addition, more complicated forms of substitution
                  usually require the braces to be present; exceptions, which only
                  apply  if  the  option  KSH_ARRAYS is not set, are a single sub-
                  script or any colon modifiers appearing after the name,  or  any
                  of the characters '^', '=', '~', '#' or '+' appearing before the
                  name, all of which work with or without braces.
                  If name is an array parameter, and the KSH_ARRAYS option is  not
                  set,  then the value of each element of name is substituted, one
                  element per word.  Otherwise, the expansion results in one  word
                  only;  with  KSH_ARRAYS,  this is the first element of an array.
                  No  field  splitting  is  done  on   the   result   unless   the
                  SH_WORD_SPLIT   option  is  set.   See  also  the  flags  =  and
                  If name is the name of a set parameter '1' is substituted,  oth-
                  erwise '0' is substituted.
                  If  name is set, or in the second form is non-null, then substi-
                  tute its value; otherwise substitute word.  In the  second  form
                  name may be omitted, in which case word is always substituted.
                  If  name is set, or in the second form is non-null, then substi-
                  tute word; otherwise substitute nothing.
                  In the first form, if name is unset then set it to word; in  the
                  second  form,  if name is unset or null then set it to word; and
                  in the third form, unconditionally set name  to  word.   In  all
                  forms, the value of the parameter is then substituted.
                  In the first form, if name is set, or in the second form if name
                  is both set and non-null, then substitute its value;  otherwise,
                  If the pattern matches the beginning of the value of name,  then
                  substitute  the  value of name with the matched portion deleted;
                  otherwise, just substitute the value  of  name.   In  the  first
                  form,  the smallest matching pattern is preferred; in the second
                  form, the largest matching pattern is preferred.
                  If the pattern matches the end of the value of name,  then  sub-
                  stitute the value of name with the matched portion deleted; oth-
                  erwise, just substitute the value of name.  In the  first  form,
                  the  smallest matching pattern is preferred; in the second form,
                  the largest matching pattern is preferred.
                  If the pattern matches the value of name,  then  substitute  the
                  empty  string; otherwise, just substitute the value of name.  If
                  name is an array the matching array elements  are  removed  (use
                  the '(M)' flag to remove the non-matched elements).
                  This  syntax  gives effects similar to parameter subscripting in
                  the form $name[start,end], but is compatible with other  shells;
                  note  that  both  offset  and length are interpreted differently
                  from the components of a subscript.
                  If offset is non-negative, then if the variable name is a scalar
                  substitute  the  contents  starting  offset  characters from the
                  first character of the string, and if name is an  array  substi-
                  tute  elements  starting offset elements from the first element.
                  If length is given, substitute that many characters or elements,
                  otherwise the entire rest of the scalar or array.
                  A positive offset is always treated as the offset of a character
                  or element in name from the first character or  element  of  the
                  array  (this  is  different from native zsh subscript notation).
                  Hence 0 refers to the first character or element  regardless  of
                  the setting of the option KSH_ARRAYS.
                  A negative offset counts backwards from the end of the scalar or
                  array, so that -1 corresponds to the last character or  element,
                  and so on.
                  When positive, length counts from the offset position toward the
                  end of the scalar or array.  When negative, length  counts  back
                  from  the  end.  If this results in a position smaller than off-
                  set, a diagnostic is printed and nothing is substituted.
                  The option MULTIBYTE is obeyed, i.e. the offset and length count
                  $foo  would  return  an  array.   Note  that  with  the   option
                  KSH_ARRAYS  $foo  always returns a scalar (regardless of the use
                  of the offset syntax) and a form such as $foo[*]:3  is  required
                  to extract elements of an array named foo.
                  If  offset  is  negative, the - may not appear immediately after
                  the : as this indicates the ${name:-word} form of  substitution.
                  Instead,  a  space  may  be inserted before the -.  Furthermore,
                  neither offset nor length may begin with an alphabetic character
                  or  & as these are used to indicate history-style modifiers.  To
                  substitute a value from a variable, the recommended approach  is
                  to  precede it with a $ as this signifies the intention (parame-
                  ter substitution can easily be rendered unreadable); however, as
                  arithmetic  substitution  is  performed,  the  expression ${var:
                  offs} does work, retrieving the offset from $offs.
                  For further compatibility with other shells there is  a  special
                  case  for  array  offset  0.  This usually accesses to the first
                  element of the array.  However, if the substitution  refers  the
                  positional parameter array, e.g. $@ or $*, then offset 0 instead
                  refers to $0, offset 1 refers to $1, and so on.  In other words,
                  the  positional  parameter  array  is  effectively  extended  by
                  prepending $0.  Hence ${*:0:1} substitutes $0 and ${*:1:1}  sub-
                  stitutes $1.
                  Replace  the  longest possible match of pattern in the expansion
                  of parameter name by string repl.  The first form replaces  just
                  the  first  occurrence,  the  second form all occurrences.  Both
                  pattern and repl are subject to double-quoted  substitution,  so
                  that  expressions  like  ${name/$opat/$npat} will work, but note
                  the usual rule that pattern characters in $opat are not  treated
                  specially  unless  either the option GLOB_SUBST is set, or $opat
                  is instead substituted as ${~opat}.
                  The pattern may begin with a '#', in which case the pattern must
                  match  at the start of the string, or '%', in which case it must
                  match at the end of the string, or '#%' in which case  the  pat-
                  tern  must  match  the  entire string.  The repl may be an empty
                  string, in which case the final '/' may  also  be  omitted.   To
                  quote  the  final  '/' in other cases it should be preceded by a
                  single backslash; this is not necessary if the '/' occurs inside
                  a  substituted  parameter.   Note also that the '#', '%' and '#%
                  are not active if they occur  inside  a  substituted  parameter,
                  even at the start.
                  The  first '/' may be preceded by a ':', in which case the match
                  will only succeed if it matches the entire word.  Note also  the
                  effect  of the I and S parameter expansion flags below; however,
                  the flags M, R, B, E and N are not useful.
                  in  characters  of  the result instead of the result itself.  If
                  spec is an array expression, substitute the number  of  elements
                  of  the result.  Note that '^', '=', and '~', below, must appear
                  to the left of '#' when these forms are combined.
                  Turn on the RC_EXPAND_PARAM option for the evaluation  of  spec;
                  if  the  '^'  is doubled, turn it off.  When this option is set,
                  array expansions of the form foo${xx}bar, where the parameter xx
                  is  set  to  (a  b  c),  are  substituted  with 'fooabar foobbar
                  foocbar' instead of the default 'fooa b  cbar'.   Note  that  an
                  empty array will therefore cause all arguments to be removed.
                  Internally, each such expansion is converted into the equivalent
                  list   for   brace    expansion.     E.g.,    ${^var}    becomes
                  {$var[1],$var[2],...}, and is processed as described in the sec-
                  tion 'Brace Expansion' below.  If  word  splitting  is  also  in
                  effect  the  $var[N] may themselves be split into different list
                  Perform word splitting using the rules for SH_WORD_SPLIT  during
                  the  evaluation of spec, but regardless of whether the parameter
                  appears in double quotes; if the '=' is doubled,  turn  it  off.
                  This forces parameter expansions to be split into separate words
                  before substitution, using IFS as a delimiter.  This is done  by
                  default in most other shells.
                  Note  that  splitting is applied to word in the assignment forms
                  of spec before  the  assignment  to  name  is  performed.   This
                  affects the result of array assignments with the A flag.
                  Turn on the GLOB_SUBST option for the evaluation of spec; if the
                  '~' is doubled, turn it off.   When  this  option  is  set,  the
                  string  resulting  from  the  expansion will be interpreted as a
                  pattern anywhere that is possible, such as in filename expansion
                  and  filename  generation and pattern-matching contexts like the
                  right hand side of the '=' and '!=' operators in conditions.
                  In nested substitutions, note that the effect of the  ~  applies
                  to the result of the current level of substitution.  A surround-
                  ing pattern operation on the result may cancel it.   Hence,  for
                  example,  if  the  parameter foo is set to *, ${~foo//\*/*.c} is
                  substituted by the pattern *.c, which may be expanded  by  file-
                  name  generation,  but  ${${~foo}//\*/*.c}  substitutes  to  the
                  string *.c, which will not be further expanded.
           If a ${...} type parameter expression or a $(...) type command  substi-
           tution  is  used  in  place of name above, it is expanded first and the
           result is used as if it were the value of name.  Thus it is possible to
           perform  nested  operations:  ${${foo#head}%tail} substitutes the value
       Parameter Expansion Flags
           If  the  opening  brace is directly followed by an opening parenthesis,
           the string up to the matching closing parenthesis will be  taken  as  a
           list of flags.  In cases where repeating a flag is meaningful, the rep-
           etitions need not be consecutive; for example, '(q%q%q)' means the same
           thing  as  the  more  readable '(%%qqq)'.  The following flags are sup-
           #      Evaluate the resulting words as numeric expressions  and  output
                  the  characters  corresponding  to  the resulting integer.  Note
                  that this form is entirely distinct from use of  the  #  without
                  If  the  MULTIBYTE  option is set and the number is greater than
                  127 (i.e. not an ASCII character) it is  treated  as  a  Unicode
           %      Expand  all  % escapes in the resulting words in the same way as
                  in prompts (see EXPANSION OF PROMPT SEQUENCES in zshmisc(1)). If
                  this  flag  is given twice, full prompt expansion is done on the
                  resulting words, depending on the setting of the PROMPT_PERCENT,
                  PROMPT_SUBST and PROMPT_BANG options.
           @      In  double  quotes,  array elements are put into separate words.
                  E.g.,  '"${(@)foo}"'  is   equivalent   to   '"${foo[@]}"'   and
                  '"${(@)foo[1,2]}"'  is  the same as '"$foo[1]" "$foo[2]"'.  This
                  is distinct from field splitting by the f, s or z  flags,  which
                  still applies within each array element.
           A      Create  an  array  parameter with '${...=...}', '${...:=...}' or
                  '${...::=...}'.  If this flag is repeated (as in  'AA'),  create
                  an associative array parameter.  Assignment is made before sort-
                  ing or padding.  The name part may be a  subscripted  range  for
                  ordinary  arrays;  the  word part must be converted to an array,
                  for example by using '${(AA)=name=...}' to activate field split-
                  ting, when creating an associative array.
           a      Sort  in  array  index  order;  when  combined  with 'O' sort in
                  reverse array index order.  Note that 'a' is  therefore  equiva-
                  lent  to the default but 'Oa' is useful for obtaining an array's
                  elements in reverse order.
           c      With ${#name}, count the total number of characters in an array,
                  as if the elements were concatenated with spaces between them.
           C      Capitalize  the resulting words.  'Words' in this case refers to
                  sequences of alphanumeric characters separated  by  non-alphanu-
                  merics, not to words that result from field splitting.
           D      Assume  the  string  or  array  elements contain directories and
                  This is a shorthand for 'pj:\n:'.
                  Process escape sequences like the echo builtin when  no  options
                  are  given (g::).  With the o option, octal escapes don't take a
                  leading zero.  With the c option, sequences like '^X'  are  also
                  processed.   With  the  e  option,  processes '\M-t' and similar
                  sequences like the print builtin.  With both  of  the  o  and  e
                  options,  behaves  like the print builtin except that in none of
                  these modes is '\c' interpreted.
           i      Sort case-insensitively.  May be combined with 'n' or 'O'.
           k      If name refers to an  associative  array,  substitute  the  keys
                  (element  names)  rather  than the values of the elements.  Used
                  with subscripts (including ordinary arrays),  force  indices  or
                  keys to be substituted even if the subscript form refers to val-
                  ues.  However, this flag may  not  be  combined  with  subscript
           L      Convert all letters in the result to lower case.
           n      Sort  decimal integers numerically; if the first differing char-
                  acters of two test strings are not digits, sorting  is  lexical.
                  Integers  with  more initial zeroes are sorted before those with
                  fewer or none.  Hence the array  'foo1  foo02  foo2  foo3  foo20
                  foo23' is sorted into the order shown.  May be combined with 'i'
                  or 'O'.
           o      Sort the resulting words in ascending order; if this appears  on
                  its  own  the  sorting is lexical and case-sensitive (unless the
                  locale renders it case-insensitive).  Sorting in ascending order
                  is the default for other forms of sorting, so this is ignored if
                  combined with 'a', 'i' or 'n'.
           O      Sort the resulting words in descending order; 'O'  without  'a',
                  'i' or 'n' sorts in reverse lexical order.  May be combined with
                  'a', 'i' or 'n' to reverse the order of sorting.
           P      This forces the value of the parameter name to be interpreted as
                  a  further parameter name, whose value will be used where appro-
                  priate.  Note that flags set with one of the typeset  family  of
                  commands (in particular case transformations) are not applied to
                  the value of name used in this fashion.
                  If used with a nested parameter  or  command  substitution,  the
                  result  of  that  will  be taken as a parameter name in the same
                  way.  For example, if you  have  'foo=bar'  and  'bar=baz',  the
                  strings  ${(P)foo},  ${(P)${foo}}, and ${(P)$(echo bar)} will be
                  expanded to 'baz'.
           q      Quote characters that are special to the shell in the  resulting
                  single  quoting is used that only quotes the string if needed to
                  protect special characters.  Typically this form gives the  most
                  readable output.
           Q      Remove one level of quotes from the resulting words.
           t      Use  a  string  describing  the  type of the parameter where the
                  value of the parameter would usually appear.  This  string  con-
                  sists  of keywords separated by hyphens ('-'). The first keyword
                  in the string  describes  the  main  type,  it  can  be  one  of
                  'scalar',  'array',  'integer',  'float'  or  'association'. The
                  other keywords describe the type in more detail:
                  local  for local parameters
                  left   for left justified parameters
                         for right justified parameters with leading blanks
                         for right justified parameters with leading zeros
                  lower  for parameters whose value is converted to all lower case
                         when it is expanded
                  upper  for parameters whose value is converted to all upper case
                         when it is expanded
                         for readonly parameters
                  tag    for tagged parameters
                  export for exported parameters
                  unique for arrays which keep only the first occurrence of dupli-
                         cated values
                  hide   for parameters with the 'hide' flag
                         for special parameters defined by the shell
           u      Expand only the first occurrence of each unique word.
           U      Convert all letters in the result to upper case.
           v      Used  with k, substitute (as two consecutive words) both the key
                  and the value of each associative array element.  Used with sub-
                  scripts,  force  values  to be substituted even if the subscript
                  form refers to indices or keys.
                  to  find  the words, i.e. taking into account any quoting in the
                  value.  Comments are  not  treated  specially  but  as  ordinary
                  strings, similar to interactive shells with the INTERACTIVE_COM-
                  MENTS option unset.
                  Note that this is done very late, as for the '(s)' flag.  So  to
                  access  single words in the result, one has to use nested expan-
                  sions as in '${${(z)foo}[2]}'. Likewise, to remove the quotes in
                  the resulting words one would do: '${(Q)${(z)foo}}'.
           0      Split  the  result  of  the  expansion on null bytes.  This is a
                  shorthand for 'ps:\0:'.
           The following flags (except p) are followed by one or more arguments as
           shown.  Any character, or the matching pairs '(...)', '{...}', '[...]',
           or '<...>', may be used in place of a colon  as  delimiters,  but  note
           that when a flag takes more than one argument, a matched pair of delim-
           iters must surround each argument.
           p      Recognize the same escape sequences  as  the  print  builtin  in
                  string arguments to any of the flags described below that follow
                  this argument.
           ~      Force string arguments to any of the  flags  below  that  follow
                  within  the parentheses to be treated as patterns.  Compare with
                  a ~ outside parentheses, which  forces  the  entire  substituted
                  string to be treated as a pattern.  Hence, for example,
                  [[ "?" = ${(~j.|.)array} ]]
           with  the  EXTENDED_GLOB option set succeeds if and only if $array con-
           tains the string '?' as an element.  The argument may  be  repeated  to
           toggle the behaviour; its effect only lasts to the end of the parenthe-
           sised group.
                  Join the words of arrays together using string as  a  separator.
                  Note  that  this  occurs before field splitting by the s:string:
                  flag or the SH_WORD_SPLIT option.
                  Pad the resulting words on the left.  Each word  will  be  trun-
                  cated if required and placed in a field expr characters wide.
                  The arguments :string1: and :string2: are optional; neither, the
                  first, or both may be given.  Note that the same pairs of delim-
                  iters  must  be used for each of the three arguments.  The space
                  to the left will be filled with string1 (concatenated  as  often
                  as  needed)  or spaces if string1 is not given.  If both string1
                  and string2 are given, string2 is inserted once directly to  the
                  left  of  each  word,  truncated if necessary, before string1 is
                  used to produce any remaining padding.
                  If the MULTIBYTE option is in effect, the flag  m  may  also  be
                  of  the  string it occupies or the overall length of the string.
                  Most printable characters have a width of one unit, however cer-
                  tain  Asian character sets and certain special effects use wider
                  characters; combining characters have zero width.  Non-printable
                  characters are arbitrarily counted as zero width; how they would
                  actually be displayed will vary.
                  If the m is repeated, the character either counts  zero  (if  it
                  has zero width), else one.  For printable character strings this
                  has the effect of counting the number of glyphs  (visibly  sepa-
                  rate characters), except for the case where combining characters
                  themselves have non-zero width (true in certain alphabets).
                  As l, but pad the words on the right and insert string2  immedi-
                  ately to the right of the string to be padded.
                  Left  and  right padding may be used together.  In this case the
                  strategy is to apply left padding to the  first  half  width  of
                  each  of  the  resulting  words, and right padding to the second
                  half.  If the string to  be  padded  has  odd  width  the  extra
                  padding is applied on the left.
                  Force  field  splitting  at  the  separator string.  Note that a
                  string of two or more characters means that  all  of  them  must
                  match  in  sequence;  this  differs from the treatment of two or
                  more characters in the IFS parameter.  See also the =  flag  and
                  the  SH_WORD_SPLIT option.  An empty string may also be given in
                  which case every character will be a separate element.
                  For historical reasons, the usual  behaviour  that  empty  array
                  elements  are  retained  inside  double  quotes  is disabled for
                  arrays generated by splitting; hence the following:
                         print -l "${(s.:.)line}"
                  produces two lines of output for one and three  and  elides  the
                  empty  field.  To override this behaviour, supply the "(@)" flag
                  as well, i.e.  "${(@s.:.)line}".
                  As z but takes a combination of option letters between a follow-
                  ing  pair of delimiter characters.  (Z+c+) causes comments to be
                  parsed as a string and retained;  any  field  in  the  resulting
                  array beginning with an unquoted comment character is a comment.
                  (Z+C+) causes comments to be parsed and removed.  The  rule  for
                  comments  is standard: anything between a word starting with the
                  third character of $HISTCHARS, default #, up to the next newline
                  is  a comment.  (Z+n+) causes unquoted newlines to be treated as
                  ordinary whitespace, else they are treated as if they are  shell
                  non-greedy matching, i.e.  that  the  shortest  instead  of  the
                  longest match should be replaced.
                  Search  the  exprth  match  (where  expr evaluates to a number).
                  This only applies when searching for substrings, either with the
                  S  flag,  or  with  ${.../...} (only the exprth match is substi-
                  tuted) or ${...//...} (all matches from the exprth on  are  sub-
                  stituted).  The default is to take the first match.
                  The  exprth  match  is  counted such that there is either one or
                  zero matches from each starting position in the string, although
                  for  global  substitution  matches overlapping previous replace-
                  ments are ignored.  With the ${...%...} and  ${...%%...}  forms,
                  the starting position for the match moves backwards from the end
                  as the index increases, while with the other forms it moves for-
                  ward from the start.
                  Hence with the string
                         which switch is the right switch for Ipswich?
                  substitutions  of  the form ${(SI:N:)string#w*ch} as N increases
                  from 1 will match  and  remove  'which',  'witch',  'witch'  and
                  'wich';  the form using '##' will match and remove 'which switch
                  is the right switch for Ipswich', 'witch is the right switch for
                  Ipswich',  'witch  for  Ipswich'  and 'wich'. The form using '%'
                  will remove the same matches as for '#', but in  reverse  order,
                  and the form using '%%' will remove the same matches as for '##'
                  in reverse order.
           B      Include the index of the beginning of the match in the result.
           E      Include the index of the end of the match in the result.
           M      Include the matched portion in the result.
           N      Include the length of the match in the result.
           R      Include the unmatched portion in the result (the Rest).
           Here is a summary of the rules  for  substitution;  this  assumes  that
           braces are present around the substitution, i.e. ${...}.  Some particu-
           lar examples are given below.  Note  that  the  Zsh  Development  Group
           accepts  no  responsibility for any brain damage which may occur during
           the reading of the following rules.
           1. Nested Substitution
                  If multiple nested ${...} forms  are  present,  substitution  is
                  performed  from the inside outwards.  At each level, the substi-
                  tution takes account of whether the current value is a scalar or
                  an  array,  whether  the whole substitution is in double quotes,
                  sion and filename expansion (i.e. leading ~ and =).   Thus,  for
                  example,  ${${:-=cat}:h}  expands to the directory where the cat
                  program resides.  (Explanation: the internal substitution has no
                  parameter  but  a default value =cat, which is expanded by file-
                  name expansion to a  full  path;  the  outer  substitution  then
                  applies  the  modifier  :h  and  takes the directory part of the
           2. Internal Parameter Flags
                  Any parameter flags set by one of the  typeset  family  of  com-
                  mands,  in particular the L, R, Z, u and l flags for padding and
                  capitalization, are applied directly to the parameter value.
           3. Parameter Subscripting
                  If the value is a raw parameter reference with a subscript, such
                  as  ${var[3]}, the effect of subscripting is applied directly to
                  the parameter.  Subscripts are evaluated left to  right;  subse-
                  quent  subscripts  apply to the scalar or array value yielded by
                  the previous subscript.  Thus if var is an  array,  ${var[1][2]}
                  is the second character of the first word, but ${var[2,4][2]} is
                  the entire third word (the second word of the range of words two
                  through  four  of the original array).  Any number of subscripts
                  may appear.
           4. Parameter Name Replacement
                  The effect of any (P) flag, which treats the value so far  as  a
                  parameter  name and replaces it with the corresponding value, is
           5. Double-Quoted Joining
                  If the value after this process is an array, and  the  substitu-
                  tion appears in double quotes, and no (@) flag is present at the
                  current level, the words of the value are joined with the  first
                  character  of  the  parameter  $IFS, by default a space, between
                  each word (single word arrays are not  modified).   If  the  (j)
                  flag is present, that is used for joining instead of $IFS.
           6. Nested Subscripting
                  Any  remaining  subscripts  (i.e.  of a nested substitution) are
                  evaluated at this point, based on whether the value is an  array
                  or  a scalar.  As with 3., multiple subscripts can appear.  Note
                  that ${foo[2,4][2]} is thus equivalent to ${${foo[2,4]}[2]}  and
                  also  to "${${(@)foo[2,4]}[2]}" (the nested substitution returns
                  an array in both cases), but  not  to  "${${foo[2,4]}[2]}"  (the
                  nested substitution returns a scalar because of the quotes).
           7. Modifiers
                  Any  modifiers, as specified by a trailing '#', '%', '/' (possi-
                  bly doubled) or by a set of modifiers of the form :... (see  the
                  section  'Modifiers'  in  the  section 'History Expansion'), are
                  applied to the words of the value at this level.
                  plies a string for joining in this manner.
           11. Case modification
                  Any  case  modification from one of the flags (L), (U) or (C) is
           12. Escape sequence replacement
                  First any replacements from the (g) flag are performed, then any
                  prompt-style formatting from the (%) family of flags is applied.
           13. Quote application
                  Any quoting or unquoting using (q) and (Q) and related flags  is
           14. Directory naming
                  Any directory name substitution using (D) flag is applied.
           15. Visibility enhancment
                  Any  modifications to make characters visible using the (V) flag
                  are applied.
           16. Forced Splitting
                  If one of the '(s)', '(f)' or '(z)' flags are  present,  or  the
                  '='  specifier  was present (e.g. ${=var}), the word is split on
                  occurrences of the specified string, or (for = with  neither  of
                  the two flags present) any of the characters in $IFS.
           17. Shell Word Splitting
                  If  no '(s)', '(f)' or '=' was given, but the word is not quoted
                  and the option SH_WORD_SPLIT is set, the word is split on occur-
                  rences  of  any of the characters in $IFS.  Note this step, too,
                  takes place at all levels of a nested substitution.
           18. Uniqueness
                  If the result is an array and the '(u)' flag was present, dupli-
                  cate elements are removed from the array.
           19. Ordering
                  If  the  result  is still an array and one of the '(o)' or '(O)'
                  flags was present, the array is reordered.
           20. Re-Evaluation
                  Any '(e)' flag is  applied  to  the  value,  forcing  it  to  be
                  re-examined  for  new parameter substitutions, but also for com-
                  mand and arithmetic substitutions.
           21. Padding
                  Any padding of the value by the '(l.fill.)' or '(r.fill.)' flags
                  is applied.
           22. Semantic Joining
                  In  contexts where expansion semantics requires a single word to
                  with other forms of substitution; the point to note here is sim-
                  ply that it occurs after any of the above parameter  operations.
           The  flag  f  is  useful  to split a double-quoted substitution line by
           line.  For example, ${(f)"$(<file)"} substitutes the contents  of  file
           divided  so  that each line is an element of the resulting array.  Com-
           pare this with the effect of $(<file) alone, which divides the file  up
           by words, or the same inside double quotes, which makes the entire con-
           tent of the file a single string.
           The following illustrates the rules for  nested  parameter  expansions.
           Suppose that $foo contains the array (bar baz):
                  This  produces  the  result  b.   First,  the inner substitution
                  "${foo}", which has no array (@) flag, produces  a  single  word
                  result "bar baz".  The outer substitution "${(@)...[1]}" detects
                  that this is a scalar, so that (despite the '(@)' flag) the sub-
                  script picks the first character.
                  This produces the result 'bar'.  In this case, the inner substi-
                  tution "${(@)foo}" produces the array '(bar  baz)'.   The  outer
                  substitution "${...[1]}" detects that this is an array and picks
                  the first word.  This is similar to the simple case "${foo[1]}".
           As an example of the rules for word splitting and joining, suppose $foo
           contains the array '(ax1 bx1)'.  Then
                  produces the words 'a', '1 b' and '1'.
                  produces 'a', '1', 'b' and '1'.
                  produces 'a' and ' b' (note the extra space).   As  substitution
                  occurs  before either joining or splitting, the operation  first
                  generates the modified array (ax bx), which is  joined  to  give
                  "ax  bx",  and  then  split to give 'a', ' b' and ''.  The final
                  empty string will then be elided, as it is not in double quotes.


           A  command  enclosed  in  parentheses  preceded  by a dollar sign, like
           '$(...)', or quoted with grave accents, like ''...'', is replaced  with
           its  standard  output, with any trailing newlines deleted.  If the sub-
           stitution is not enclosed in double quotes, the output is  broken  into
           words  using  the  IFS parameter.  The substitution '$(cat foo)' may be
           replaced by the equivalent but faster '$(<foo)'.  In  either  case,  if
           An expression of the form '{n1..n2}', where n1 and n2 are integers,  is
           expanded to every number between n1 and n2 inclusive.  If either number
           begins with a zero, all the resulting numbers will be padded with lead-
           ing  zeroes to that minimum width, but for negative numbers the - char-
           acter is also included in the width.  If the numbers are in  decreasing
           order the resulting sequence will also be in decreasing order.
           An  expression  of  the  form  '{n1..n2..n3}', where n1, n2, and n3 are
           integers, is expanded as above, but only  every  n3th  number  starting
           from n1 is output.  If n3 is negative the numbers are output in reverse
           order, this is slightly different from simply swapping n1 and n2 in the
           case  that  the  step n3 doesn't evenly divide the range.  Zero padding
           can be specified in any of the three  numbers,  specifying  it  in  the
           third  can  be  useful to pad for example '{-99..100..01}' which is not
           possible to specify by putting a 0 on either of the first  two  numbers
           (i.e. pad to two characters).
           If  a  brace  expression  matches  none  of the above forms, it is left
           unchanged, unless the option  BRACE_CCL  (an  abbreviation  for  'brace
           character  class')  is  set.  In that case, it is expanded to a list of
           the individual characters between the braces sorted into the  order  of
           the characters in the ASCII character set (multibyte characters are not
           currently handled).  The syntax is similar to  a  [...]  expression  in
           filename  generation:  '-'  is  treated  specially to denote a range of
           characters, but '^' or '!' as the first character is treated  normally.
           For  example, '{abcdef0-9}' expands to 16 words 0 1 2 3 4 5 6 7 8 9 a b
           c d e f.
           Note that brace expansion is not part  of  filename  generation  (glob-
           bing);  an  expression  such  as */{foo,bar} is split into two separate
           words */foo and */bar before filename generation takes place.  In  par-
           ticular,  note  that  this  is  liable to produce a 'no match' error if
           either of the two expressions does not match; this is to be  contrasted
           with  */(foo|bar),  which  is treated as a single pattern but otherwise
           has similar effects.
           To combine brace expansion with array expansion, see the ${^spec}  form
           described in the section Parameter Expansion above.


           Each  word  is checked to see if it begins with an unquoted '~'.  If it
           does, then the word up to a '/', or the end of the word if there is  no
           '/',  is  checked  to  see  if it can be substituted in one of the ways
           described here.  If so, then  the  '~'  and  the  checked  portion  are
           replaced with the appropriate substitute value.
           A '~' by itself is replaced by the value of $HOME.  A '~' followed by a
           '+' or a '-' is replaced by  current  or  previous  working  directory,
           names,  then the functions are used to implement dynamic directory nam-
           ing.  The functions are tried in order until one returns  status  zero,
           so it is important that functions test whether they can handle the case
           in question and return an appropriate status.
           A '~' followed by a  string  namstr  in  unquoted  square  brackets  is
           treated  specially  as  a  dynamic directory name.  Note that the first
           unquoted closing square bracket always terminates  namstr.   The  shell
           function  is  passed two arguments: the string n (for name) and namstr.
           It should either set the array reply to a single element which  is  the
           directory  corresponding  to the name and return status zero (executing
           an assignment as the last  statement  is  usually  sufficient),  or  it
           should return status non-zero.  In the former case the element of reply
           is used as the directory; in the latter case the substitution is deemed
           to  have  failed.  If all functions fail and the option NOMATCH is set,
           an error results.
           The functions defined as above are also used to see if a directory  can
           be turned into a name, for example when printing the directory stack or
           when expanding %~ in prompts.  In this case each function is passed two
           arguments:  the  string d (for directory) and the candidate for dynamic
           naming.  The function should either  return  non-zero  status,  if  the
           directory  cannot  be named by the function, or it should set the array
           reply to consist of two elements: the first is the dynamic name for the
           directory (as would appear within '~[...]'), and the second is the pre-
           fix length of the directory to be replaced.  For example, if the  trial
           directory   is   /home/myname/src/zsh   and   the   dynamic   name  for
           /home/myname/src (which has 16 characters) is s, then the function sets
                  reply=(s 16)
           The  directory  name so returned is compared with possible static names
           for parts of the directory path, as described below; it is used if  the
           prefix  length  matched (16 in the example) is longer than that matched
           by any static name.
           It is not a requirement that a function implements both n and d  calls;
           for  example,  it  might  be  appropriate  for certain dynamic forms of
           expansion not to be contracted to names.  In that case  any  call  with
           the first argument d should cause a non-zero status to be returned.
           The  completion system calls 'zsh_directory_name c' followed by equiva-
           lent calls to elements of the array zsh_directory_name_functions, if it
           exists,  in  order to complete dynamic names for directories.  The code
           for this should be as for any other completion function as described in
           As a working example, here is a function that expands any dynamic names
           beginning with the string p: to directories  below  /home/pws/perforce.
           In  this  simple  case a static name for the directory would be just as
                      [[ $2 != (#b)p:(?*) ]] && return 1
                      typeset -ga reply
                    elif [[ $1 = c ]]; then
                      # complete names
                      local expl
                      local -a dirs
                      _wanted dynamic-dirs expl 'dynamic directory' compadd -S\] -a dirs
                      return 1
                    return 0
       Static named directories
           A '~' followed by anything not already covered consisting of any number
           of  alphanumeric  characters  or underscore ('_'), hyphen ('-'), or dot
           ('.') is looked up as a named directory, and replaced by the  value  of
           that  named  directory  if found.  Named directories are typically home
           directories for users on the system.  They may also be defined  if  the
           text  after the '~' is the name of a string shell parameter whose value
           begins with a '/'.  Note that trailing slashes will be removed from the
           path  to the directory (though the original parameter is not modified).
           It is also possible to define directory names using the  -d  option  to
           the hash builtin.
           In  certain  circumstances  (in  prompts, for instance), when the shell
           prints a path, the path is checked to see if it has a  named  directory
           as  its  prefix.  If so, then the prefix portion is replaced with a '~'
           followed by the name of the directory.  The shortest way  of  referring
           to  the  directory is used, with ties broken in favour of using a named
           directory, except when the directory is / itself.  The parameters  $PWD
           and $OLDPWD are never abbreviated in this fashion.
       '=' expansion
           If a word begins with an unquoted '=' and the EQUALS option is set, the
           remainder of the word is taken as the name of a command.  If a  command
           exists  by  that name, the word is replaced by the full pathname of the
           Filename expansion is performed on the right hand side of  a  parameter
           assignment,  including  those  appearing  after commands of the typeset
           family.  In this case, the  right  hand  side  will  be  treated  as  a
           colon-separated list in the manner of the PATH parameter, so that a '~'
           generation, unless the GLOB option  is  unset.   If  the  EXTENDED_GLOB
           option is set, the '^' and '#' characters also denote a pattern; other-
           wise they are not treated specially by the shell.
           The word is replaced with a list of sorted  filenames  that  match  the
           pattern.   If  no  matching  pattern is found, the shell gives an error
           message, unless the NULL_GLOB option is set, in which case the word  is
           deleted;  or unless the NOMATCH option is unset, in which case the word
           is left unchanged.
           In filename generation, the character '/' must be  matched  explicitly;
           also, a '.' must be matched explicitly at the beginning of a pattern or
           after a '/', unless the GLOB_DOTS option is set.  No  filename  genera-
           tion pattern matches the files '.' or '..'.  In other instances of pat-
           tern matching, the '/' and '.' are not treated specially.
       Glob Operators
           *      Matches any string, including the null string.
           ?      Matches any character.
           [...]  Matches any of the enclosed characters.   Ranges  of  characters
                  can  be  specified by separating two characters by a '-'.  A '-'
                  or ']' may be matched by including it as the first character  in
                  the  list.   There are also several named classes of characters,
                  in the form '[:name:]' with the following meanings.   The  first
                  set  use the macros provided by the operating system to test for
                  the given character combinations,  including  any  modifications
                  due to local language settings, see ctype(3):
                         The character is alphanumeric
                         The character is alphabetic
                         The  character  is 7-bit, i.e. is a single-byte character
                         without the top bit set.
                         The character is either space or tab
                         The character is a control character
                         The character is a decimal digit
                         The character is a printable character other than whites-
                         The character is an uppercase letter
                         The character is a hexadecimal digit
                  Another set of named classes is handled internally by the  shell
                  and is not sensitive to the locale:
                         The  character is allowed to form part of a shell identi-
                         fier, such as a parameter name
                         The character is used as an input field  separator,  i.e.
                         is contained in the IFS parameter
                         The  character  is  an IFS white space character; see the
                         documentation for IFS in the zshparam(1) manual page.
                         The character is treated as part of a word; this test  is
                         sensitive to the value of the WORDCHARS parameter
                  Note  that the square brackets are additional to those enclosing
                  the whole set of characters, so to test for  a  single  alphanu-
                  meric  character  you  need '[[:alnum:]]'.  Named character sets
                  can be used alongside other types, e.g. '[[:alpha:]0-9]'.
           [!...] Like [...], except that it matches any character which is not in
                  the given set.
                  Matches  any  number  in the range x to y, inclusive.  Either of
                  the numbers may be omitted to make the range  open-ended;  hence
                  '<->' matches any number.  To match individual digits, the [...]
                  form is more efficient.
                  Be careful when using other wildcards adjacent  to  patterns  of
                  this  form;  for  example, <0-9>* will actually match any number
                  whatsoever at the start of the string, since  the  '<0-9>'  will
                  match  the first digit, and the '*' will match any others.  This
                  is a trap for the unwary, but is in fact  an  inevitable  conse-
                  quence  of  the rule that the longest possible match always suc-
                  ceeds.  Expressions such as  '<0-9>[^[:digit:]]*'  can  be  used
           (...)  Matches  the  enclosed  pattern.  This is used for grouping.  If
                  the KSH_GLOB option is set, then a '@', '*',  '+',  '?'  or  '!'
                  immediately  preceding the '(' is treated specially, as detailed
           ^x     (Requires EXTENDED_GLOB to be set.)  Matches anything except the
                  pattern x.  This has a higher precedence than '/', so '^foo/bar'
                  will  search  directories in '.' except './foo' for a file named
           x~y    (Requires EXTENDED_GLOB to be set.)  Match anything that matches
                  the  pattern  x but does not match y.  This has lower precedence
                  than any operator except '|', so '*/*~foo/bar' will  search  for
                  all  files in all directories in '.'  and then exclude 'foo/bar'
                  if there was such a match.  Multiple patterns can be excluded by
                  'foo~bar~baz'.   In  the  exclusion pattern (y), '/' and '.' are
                  not treated specially the way they usually are in globbing.
           x#     (Requires EXTENDED_GLOB to be set.)  Matches zero or more occur-
                  rences  of  the  pattern  x.  This operator has high precedence;
                  '12#' is equivalent to '1(2#)', rather than '(12)#'.  It  is  an
                  error  for  an  unquoted '#' to follow something which cannot be
                  repeated; this includes an empty string, a pattern already  fol-
                  lowed  by  '##',  or parentheses when part of a KSH_GLOB pattern
                  (for example, '!(foo)#' is  invalid  and  must  be  replaced  by
           x##    (Requires  EXTENDED_GLOB to be set.)  Matches one or more occur-
                  rences of the pattern x.  This  operator  has  high  precedence;
                  '12##' is equivalent to '1(2##)', rather than '(12)##'.  No more
                  than two active '#' characters may appear together.   (Note  the
                  potential  clash with glob qualifiers in the form '1(2##)' which
                  should therefore be avoided.)
       ksh-like Glob Operators
           If the KSH_GLOB option is set, the effects of parentheses can be  modi-
           fied by a preceding '@', '*', '+', '?' or '!'.  This character need not
           be unquoted to have special effects, but the '(' must be.
           @(...) Match the pattern in the parentheses.  (Like '(...)'.)
           *(...) Match any number of occurrences.  (Like '(...)#'.)
           +(...) Match at least one occurrence.  (Like '(...)##'.)
           ?(...) Match zero or one occurrence.  (Like '(|...)'.)
           !(...) Match  anything  but  the  expression  in  parentheses.    (Like
           The precedence of the operators given above is (highest) '^', '/', '~',
           '|' (lowest); the remaining operators are simply treated from  left  to
           right  as  part of a string, with '#' and '##' applying to the shortest
           possible preceding unit (i.e. a character, '?', '[...]', '<...>', or  a
           parenthesised  expression).  As mentioned above, a '/' used as a direc-
           tory separator may not appear inside parentheses, while a '|'  must  do
           l      Lower case characters in the pattern match upper or  lower  case
                  characters;  upper  case  characters  in  the pattern still only
                  match upper case characters.
           I      Case sensitive:  locally negates the effect of i or l from  that
                  point on.
           b      Activate backreferences for parenthesised groups in the pattern;
                  this does not work in filename generation.  When a pattern  with
                  a  set  of active parentheses is matched, the strings matched by
                  the groups are stored in the array $match, the  indices  of  the
                  beginning  of  the matched parentheses in the array $mbegin, and
                  the indices of the end in the array $mend, with the  first  ele-
                  ment  of  each  array  corresponding  to the first parenthesised
                  group, and so on.  These arrays are not otherwise special to the
                  shell.   The  indices  use the same convention as does parameter
                  substitution, so that elements of $mend and $mbegin may be  used
                  in  subscripts;  the  KSH_ARRAYS  option  is respected.  Sets of
                  globbing flags are not considered parenthesised groups; only the
                  first nine active parentheses can be referenced.
                  For example,
                         foo="a string with a message"
                         if [[ $foo = (a|an)' '(#b)(*)' '* ]]; then
                           print ${foo[$mbegin[1],$mend[1]]}
                  prints  'string  with  a'.   Note  that the first parenthesis is
                  before the (#b) and does not create a backreference.
                  Backreferences work with all forms  of  pattern  matching  other
                  than  filename generation, but note that when performing matches
                  on an entire array, such as ${array#pattern}, or a  global  sub-
                  stitution,  such  as  ${param//pat/repl},  only the data for the
                  last match remains available.  In the case  of  global  replace-
                  ments  this may still be useful.  See the example for the m flag
                  The numbering of backreferences strictly follows  the  order  of
                  the  opening  parentheses  from  left  to  right  in the pattern
                  string, although sets of parentheses may be nested.   There  are
                  special rules for parentheses followed by '#' or '##'.  Only the
                  last match of the parenthesis is remembered: for example, in '[[
                  abab  =  (#b)([ab])#  ]]',  only  the  final  'b'  is  stored in
                  match[1].  Thus extra parentheses may be necessary to match  the
                  complete  segment:  for  example,  use 'X((ab|cd)#)Y' to match a
                  whole string of either 'ab' or 'cd' between 'X' and  'Y',  using
                  the value of $match[1] rather than $match[2].
                  If the match fails none of the parameters is altered, so in some
                  cases it may be necessary to  initialise  them  beforehand.   If
                  filename generation, where '/' has special meaning; it cannot be
                  combined with other globbing  flags  and  a  bad  pattern  error
                  occurs  if  it is misplaced.  It is equivalent to the form {N,M}
                  in regular expressions.  The  previous  character  or  group  is
                  required  to  match  between N and M times, inclusive.  The form
                  (#cN) requires exactly N matches; (#c,M) is equivalent to speci-
                  fying N as 0; (#cN,) specifies that there is no maximum limit on
                  the number of matches.
           m      Set references to the match data for the entire string  matched;
                  this is similar to backreferencing and does not work in filename
                  generation.  The flag must be in effect at the end of  the  pat-
                  tern, i.e. not local to a group. The parameters $MATCH,  $MBEGIN
                  and $MEND will be set to the string matched and to  the  indices
                  of  the  beginning and end of the string, respectively.  This is
                  most useful in parameter substitutions, as otherwise the  string
                  matched is obvious.
                  For example,
                         arr=(veldt jynx grimps waqf zho buck)
                         print ${arr//(#m)[aeiou]/${(U)MATCH}}
                  forces  all the matches (i.e. all vowels) into uppercase, print-
                  ing 'vEldt jynx grImps wAqf zhO bUck'.
                  Unlike backreferences, there is no speed penalty for using match
                  references,  other than the extra substitutions required for the
                  replacement strings in cases such as the example shown.
           M      Deactivate the m flag, hence no references to match data will be
           anum   Approximate  matching:  num  errors  are  allowed  in the string
                  matched by the pattern.  The rules for this are described in the
                  next subsection.
           s, e   Unlike the other flags, these have only a local effect, and each
                  must appear on its own:  '(#s)' and '(#e)' are  the  only  valid
                  forms.   The  '(#s)' flag succeeds only at the start of the test
                  string, and the '(#e)' flag succeeds only at the end of the test
                  string;  they  correspond  to  '^'  and  '$' in standard regular
                  expressions.  They are useful for matching path segments in pat-
                  terns  other  than those in filename generation (where path seg-
                  ments  are  in  any  case  treated  separately).   For  example,
                  '*((#s)|/)test((#e)|/)*' matches a path segment 'test' in any of
                  the  following  strings:   test,   test/at/start,   at/end/test,
                  Another   use   is   in   parameter  substitution;  for  example
                  '${array/(#s)A*Z(#e)}' will remove only  elements  of  an  array
                  which match the complete pattern 'A*Z'.  There are other ways of
                  globbing and for matching against a string.  In the former case,
                  the  '(#q.)'  will be treated as a glob qualifier and the '(#b)'
                  will not be useful, while in the latter case the '(#b)' is  use-
                  ful  for  backreferences  and the '(#q.)' will be ignored.  Note
                  that colon modifiers in the glob qualifiers are also not applied
                  in ordinary pattern matching.
           u      Respect the current locale in determining the presence of multi-
                  byte characters in a pattern, provided the  shell  was  compiled
                  with  MULTIBYTE_SUPPORT.   This  overrides the MULTIBYTE option;
                  the default behaviour is taken  from  the  option.   Compare  U.
                  (Mnemonic:  typically  multibyte  characters are from Unicode in
                  the UTF-8 encoding, although any extension of ASCII supported by
                  the system library may be used.)
           U      All  characters  are  considered  to be a single byte long.  The
                  opposite of u.  This overrides the MULTIBYTE option.
           For example, the test string  fooxx  can  be  matched  by  the  pattern
           (#i)FOOXX,  but  not  by  (#l)FOOXX, (#i)FOO(#I)XX or ((#i)FOOX)X.  The
           string (#ia2)readme specifies case-insensitive matching of readme  with
           up to two errors.
           When  using the ksh syntax for grouping both KSH_GLOB and EXTENDED_GLOB
           must be set and the left parenthesis should be  preceded  by  @.   Note
           also that the flags do not affect letters inside [...] groups, in other
           words (#i)[a-z] still matches only lowercase  letters.   Finally,  note
           that when examining whole paths case-insensitively every directory must
           be searched for all files which match, so that a pattern  of  the  form
           (#i)/foo/bar/... is potentially slow.
       Approximate Matching
           When  matching  approximately,  the  shell  keeps a count of the errors
           found, which cannot exceed the number specified in the  (#anum)  flags.
           Four types of error are recognised:
           1.     Different characters, as in fooxbar and fooybar.
           2.     Transposition of characters, as in banana and abnana.
           3.     A  character  missing  in the target string, as with the pattern
                  road and target string rod.
           4.     An extra character appearing in the target string, as with stove
                  and strove.
           Thus,  the pattern (#a3)abcd matches dcba, with the errors occurring by
           using the first rule twice and the second once, grouping the string  as
           [d][cb][a] and [a][bc][d].
           Non-literal  parts of the pattern must match exactly, including charac-
           as all such forms are now excluded.
           Apart from exclusions, there is only one overall error count;  however,
           the  maximum  errors  allowed  may  be altered locally, and this can be
           delimited by grouping.  For example, (#a1)cat((#a0)dog)fox  allows  one
           error in total, which may not occur in the dog section, and the pattern
           (#a1)cat(#a0)dog(#a1)fox is equivalent.  Note that the point  at  which
           an  error is first found is the crucial one for establishing whether to
           use  approximation;  for  example,  (#a1)abc(#a0)xyz  will  not   match
           abcdxyz,  because  the  error occurs at the 'x', where approximation is
           turned off.
           Entire  path  segments  may   be   matched   approximately,   so   that
           '(#a1)/foo/d/is/available/at/the/bar' allows one error in any path seg-
           ment.  This is much less efficient than  without  the  (#a1),  however,
           since  every  directory  in  the  path  must  be scanned for a possible
           approximate match.  It is best to place the (#a1) after any  path  seg-
           ments which are known to be correct.
       Recursive Globbing
           A pathname component of the form '(foo/)#' matches a path consisting of
           zero or more directories matching the pattern foo.
           As a shorthand, '**/' is equivalent to '(*/)#'; note that  this  there-
           fore  matches files in the current directory as well as subdirectories.
                  ls (*/)#bar
                  ls **/bar
           does a recursive directory search for files  named  'bar'  (potentially
           including the file 'bar' in the current directory).  This form does not
           follow symbolic links; the alternative form '***/' does, but is  other-
           wise  identical.   Neither of these can be combined with other forms of
           globbing within the same path segment; in that case, the '*'  operators
           revert to their usual effect.
       Glob Qualifiers
           Patterns  used  for filename generation may end in a list of qualifiers
           enclosed in parentheses.  The qualifiers specify which  filenames  that
           otherwise  match  the  given  pattern  will be inserted in the argument
           If the option BARE_GLOB_QUAL is set, then a trailing set of parentheses
           containing  no '|' or '(' characters (or '~' if it is special) is taken
           as a set of glob qualifiers.  A glob subexpression that would  normally
           be  taken  as  glob qualifiers, for example '(^x)', can be forced to be
           treated as part of the glob pattern by  doubling  the  parentheses,  in
           avoided for the sake of clarity.
           A qualifier may be any one of the following:
           /      directories
           F      'full'  (i.e.  non-empty)  directories.   Note that the opposite
                  sense (^F) expands to empty directories and all non-directories.
                  Use (/^F) for empty directories.
           .      plain files
           @      symbolic links
           =      sockets
           p      named pipes (FIFOs)
           *      executable plain files (0100)
           %      device files (character or block special)
           %b     block special files
           %c     character special files
           r      owner-readable files (0400)
           w      owner-writable files (0200)
           x      owner-executable files (0100)
           A      group-readable files (0040)
           I      group-writable files (0020)
           E      group-executable files (0010)
           R      world-readable files (0004)
           W      world-writable files (0002)
           X      world-executable files (0001)
           s      setuid files (04000)
           S      setgid files (02000)
           t      files with the sticky bit (01000)
           fspec  files with access rights matching spec. This spec may be a octal
                  number optionally preceded by a '=', a '+', or a '-'. If none of
                  may  be  either  an octal number as described above or a list of
                  any of the characters 'u', 'g', 'o', and 'a', followed by a '=',
                  a  '+',  or  a  '-', followed by a list of any of the characters
                  'r', 'w', 'x', 's', and 't', or an octal digit. The  first  list
                  of  characters specify which access rights are to be checked. If
                  a 'u' is given, those for the owner of the file are used,  if  a
                  'g'  is  given,  those  of the group are checked, a 'o' means to
                  test those of other users, and the 'a' says to  test  all  three
                  groups. The '=', '+', and '-' again says how the modes are to be
                  checked and have the same meaning as  described  for  the  first
                  form  above.  The  second  list of characters finally says which
                  access rights are to be expected: 'r' for read access,  'w'  for
                  write  access,  'x'  for  the  right  to execute the file (or to
                  search a directory), 's' for the setuid and setgid bits, and 't'
                  for the sticky bit.
                  Thus,  '*(f70?)'  gives  the files for which the owner has read,
                  write, and execute permission, and for which other group members
                  have  no rights, independent of the permissions for other users.
                  The pattern '*(f-100)' gives all files for which the owner  does
                  not  have  execute  permission,  and '*(f:gu+w,o-rx:)' gives the
                  files for which the owner and the other  members  of  the  group
                  have  at least write permission, and for which other users don't
                  have read or execute permission.
           +cmd   The string will be executed as shell code.  The filename will be
                  included in the list if and only if the code returns a zero sta-
                  tus (usually the status of the last command).
                  In the first form, the first character after  the  'e'  will  be
                  used as a separator and anything up to the next matching separa-
                  tor will be taken  as the string; '[', '{', and '<'  match  ']',
                  '}',  and  '>',  respectively, while any other character matches
                  itself. Note that expansions must be quoted  in  the  string  to
                  prevent  them  from  being  expanded  before  globbing  is done.
                  string is then executed as shell code.  The string  globqual  is
                  appended  to  the  array zsh_eval_context the duration of execu-
                  During the execution of  string  the  filename  currently  being
                  tested is available in the parameter REPLY; the parameter may be
                  altered to a string to be inserted into the list instead of  the
                  original  filename.  In addition, the parameter reply may be set
                  to an array or a string, which overrides the value of REPLY.  If
                  set  to  an  array, the latter is inserted into the command line
                  word by word.
                  For  example,  suppose  a  directory  contains  a  single   file
                  'lonely'.   Then  the expression '*(e:'reply=(${REPLY}{1,2})':)'
                  will cause the words 'lonely1' and 'lonely2' to be inserted into
                  the command line.  Note the quoting of string.
           ddev   files on the device dev
                  files having a link count less than ct (-), greater than ct (+),
                  or equal to ct
           U      files owned by the effective user ID
           G      files owned by the effective group ID
           uid    files  owned  by  user ID id if that is a number.  Otherwise, id
                  specifies a user name: the character after the 'u' will be taken
                  as  a  separator and the string between it and the next matching
                  separator will be taken as a user name.  The starting separators
                  '[',  '{', and '<' match the final separators ']', '}', and '>',
                  respectively; any other character matches itself.  The  selected
                  files  are  those  owned by this user.  For example, 'u:foo:' or
                  'u[foo]' selects files owned by user 'foo'.
           gid    like uid but with group IDs or names
                  files accessed exactly n days ago.  Files  accessed  within  the
                  last  n  days  are  selected  using a negative value for n (-n).
                  Files accessed more than n days ago are selected by a positive n
                  value  (+n).  Optional unit specifiers 'M', 'w', 'h', 'm' or 's'
                  (e.g. 'ah5') cause the check to be performed with months (of  30
                  days), weeks, hours, minutes or seconds instead of days, respec-
                  tively.  An explicit 'd' for days is also allowed.
                  Any fractional part of the difference between  the  access  time
                  and  the current part in the appropriate units is ignored in the
                  comparison.  For  instance,  'echo  *(ah-5)'  would  echo  files
                  accessed  within the last five hours, while 'echo *(ah+5)' would
                  echo files accessed at least six hours ago,  as  times  strictly
                  between five and six hours are treated as five hours.
                  like  the  file  access  qualifier, except that it uses the file
                  modification time.
                  like the file access qualifier, except that  it  uses  the  file
                  inode change time.
                  files less than n bytes (-), more than n bytes (+), or exactly n
                  bytes in length.
                  If this flag is directly followed by a 'k' ('K'), 'm' ('M'),  or
                  'p'  ('P') (e.g. 'Lk-50') the check is performed with kilobytes,
                  megabytes, or blocks (of 512 bytes) instead.   In  this  case  a
           T      appends a trailing qualifier mark to the filenames, analogous to
                  the LIST_TYPES option, for the current pattern (overrides M)
           N      sets the NULL_GLOB option for the current pattern
           D      sets the GLOB_DOTS option for the current pattern
           n      sets the NUMERIC_GLOB_SORT option for the current pattern
           oc     specifies how the names of the files should be sorted. If c is n
                  they  are  sorted  by  name  (the  default); if it is L they are
                  sorted depending on the size (length) of the files;  if  l  they
                  are sorted by the number of links; if a, m, or c they are sorted
                  by the time of the last access, modification,  or  inode  change
                  respectively;  if d, files in subdirectories appear before those
                  in the current directory at each level of the search -- this  is
                  best combined with other criteria, for example 'odon' to sort on
                  names for files within the same directory; if N, no  sorting  is
                  performed.   Note  that  a, m, and c compare the age against the
                  current time, hence the first name in the list is  the  youngest
                  file.  Also  note  that  the  modifiers  ^  and  -  are used, so
                  '*(^-oL)' gives a list of all  files  sorted  by  file  size  in
                  descending  order,  following  any symbolic links.  Unless oN is
                  used, multiple order specifiers may occur to resolve ties.
                  oe and o+ are special cases; they are  each  followed  by  shell
                  code, delimited as for the e glob qualifier and the + glob qual-
                  ifier respectively (see above).  The code is executed  for  each
                  matched  file  with  the  parameter REPLY set to the name of the
                  file on entry and globsort appended  to  zsh_eval_context.   The
                  code  should  modify  the  parameter  REPLY in some fashion.  On
                  return, the value of the parameter is used instead of  the  file
                  name  as  the string on which to sort.  Unlike other sort opera-
                  tors, oe and o+ may be repeated, but note that the maximum  num-
                  ber  of  sort  operators of any kind that may appear in any glob
                  expression is 12.
           Oc     like 'o', but sorts in descending order; i.e.  '*(^oc)'  is  the
                  same  as  '*(Oc)' and '*(^Oc)' is the same as '*(oc)'; 'Od' puts
                  files in the current directory before those in subdirectories at
                  each level of the search.
                  specifies  which  of the matched filenames should be included in
                  the returned list. The syntax is the  same  as  for  array  sub-
                  scripts.  beg  and  the optional end may be mathematical expres-
                  sions. As in parameter subscripting they may be negative to make
                  them  count  from  the  last match backward. E.g.: '*(-OL[1,3])'
                  gives a list of the names of the three largest files.
                  The string will be prepended to each glob match  as  a  separate
           which  they  are  given.   These are the qualifiers 'M', 'T', 'N', 'D',
           'n', 'o', 'O' and the subscripts given in brackets ('[...]').
           If a ':' appears in a qualifier list, the remainder of  the  expression
           in  parenthesis  is  interpreted  as a modifier (see the section 'Modi-
           fiers' in the section 'History  Expansion').   Each  modifier  must  be
           introduced  by a separate ':'.  Note also that the result after modifi-
           cation does not have to be an existing file.  The name of any  existing
           file  can  be  followed  by  a  modifier of the form '(:..)' even if no
           actual filename generation is performed, although note that  the  pres-
           ence of the parentheses causes the entire expression to be subjected to
           any global pattern matching options such as NULL_GLOB. Thus:
                  ls *(-/)
           lists all directories and symbolic links that point to directories, and
                  ls *(%W)
           lists all world-writable device files in the current directory, and
                  ls *(W,X)
           lists  all  files  in  the current directory that are world-writable or
           world-executable, and
                  echo /tmp/foo*(u0^@:t)
           outputs the basename of all root-owned files beginning with the  string
           'foo' in /tmp, ignoring symlinks, and
                  ls *.*~(lex|parse).[ch](^D^l1)
           lists  all  files  having a link count of one whose names contain a dot
           (but not those starting with  a  dot,  since  GLOB_DOTS  is  explicitly
           switched off) except for lex.c, lex.h, parse.c and parse.h.
                  print b*.pro(#q:s/pro/shmo/)(#q.:s/builtin/shmiltin/)
           demonstrates  how  colon  modifiers and other qualifiers may be chained
           together.  The ordinary qualifier '.' is applied first, then the  colon
           modifiers  in order from left to right.  So if EXTENDED_GLOB is set and
           the base pattern matches the regular file, the  shell  will
           print 'shmiltin.shmo'.

    zsh 4.3.17 February 22, 2011 ZSHEXPN(1)


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