LinuxGuruz
  • Last 5 Forum Topics
    Replies
    Views
    Last post


The Web Only This Site
  • BOOKMARK

  • ADD TO FAVORITES

  • REFERENCES


  • MARC

    Mailing list ARChives
    - Search by -
     Subjects
     Authors
     Bodies





    FOLDOC

    Computing Dictionary




  • Text Link Ads






  • LINUX man pages
  • Linux Man Page Viewer


    The following form allows you to view linux man pages.

    Command:

    zshmisc

    
    
    

    SIMPLE COMMANDS & PIPELINES

           A  simple  command is a sequence of optional parameter assignments fol-
           lowed by  blank-separated  words,  with  optional  redirections  inter-
           spersed.  The first word is the command to be executed, and the remain-
           ing words, if any, are arguments to the command.  If a command name  is
           given,  the parameter assignments modify the environment of the command
           when it is executed.  The value of a simple command is its exit status,
           or 128 plus the signal number if terminated by a signal.  For example,
    
                  echo foo
    
           is a simple command with arguments.
    
           A  pipeline  is  either  a simple command, or a sequence of two or more
           simple commands where each command is separated from the next by '|' or
           '|&'.   Where commands are separated by '|', the standard output of the
           first command is connected to the standard input of the next.  '|&'  is
           shorthand for '2>&1 |', which connects both the standard output and the
           standard error of the command to the standard input of the  next.   The
           value  of  a  pipeline  is  the  value  of the last command, unless the
           pipeline is preceded by '!' in which case  the  value  is  the  logical
           inverse of the value of the last command.  For example,
    
                  echo foo | sed 's/foo/bar/'
    
           is  a  pipeline,  where  the output ('foo' plus a newline) of the first
           command will be passed to the input of the second.
    
           If a pipeline is preceded by 'coproc', it is executed as a coprocess; a
           two-way pipe is established between it and the parent shell.  The shell
           can read from or write to the coprocess by means of the '>&p' and '<&p'
           redirection  operators  or  with  'print -p' and 'read -p'.  A pipeline
           cannot be preceded by both 'coproc' and '!'.  If job control is active,
           the coprocess can be treated in other than input and output as an ordi-
           nary background job.
    
           A sublist is either a single pipeline, or a sequence  of  two  or  more
           pipelines separated by '&&' or '||'.  If two pipelines are separated by
           '&&', the second pipeline  is  executed  only  if  the  first  succeeds
           (returns  a  zero status).  If two pipelines are separated by '||', the
           second is executed only if the first fails (returns a nonzero  status).
           Both  operators  have  equal  precedence and are left associative.  The
           value of the sublist is the value of the last pipeline  executed.   For
           example,
    
                  dmesg | grep panic && print yes
    
           is a sublist consisting of two pipelines, the second just a simple com-
           mand which will be executed if and only if the grep command  returns  a
           zero  status.   If it does not, the value of the sublist is that return
           status, else it is the status returned by the print  (almost  certainly
           zero).
           the word 'list' appears in later descriptions.  For example,  the  com-
           mands in a shell function form a special sort of list.
    
    
    

    PRECOMMAND MODIFIERS

           A  simple  command may be preceded by a precommand modifier, which will
           alter how the  command  is  interpreted.   These  modifiers  are  shell
           builtin  commands  with  the exception of nocorrect which is a reserved
           word.
    
           -      The command is executed with a  '-'  prepended  to  its  argv[0]
                  string.
    
           builtin
                  The  command  word is taken to be the name of a builtin command,
                  rather than a shell function or external command.
    
           command [ -pvV ]
                  The command word is taken to be the name of an external command,
                  rather than a shell function or builtin.   If the POSIX_BUILTINS
                  option is set, builtins will also be executed but  certain  spe-
                  cial  properties  of  them  are suppressed. The -p flag causes a
                  default path to be searched instead of that in $path.  With  the
                  -v flag, command is similar to whence and with -V, it is equiva-
                  lent to whence -v.
    
           exec [ -cl ] [ -a argv0 ]
                  The following command together with  any  arguments  is  run  in
                  place of the current process, rather than as a sub-process.  The
                  shell does not fork and is replaced.  The shell does not  invoke
                  TRAPEXIT,  nor  does  it  source zlogout files.  The options are
                  provided for compatibility with other shells.
    
                  The -c option clears the environment.
    
                  The -l option is equivalent to the  -  precommand  modifier,  to
                  treat  the  replacement command as a login shell; the command is
                  executed with a - prepended to its argv[0]  string.   This  flag
                  has no effect if used together with the -a option.
    
                  The  -a  option is used to specify explicitly the argv[0] string
                  (the name of the command as seen by the process  itself)  to  be
                  used  by  the  replacement command and is directly equivalent to
                  setting a value for the ARGV0 environment variable.
    
           nocorrect
                  Spelling correction is not done on any of the words.  This  must
                  appear  before  any  other  precommand modifier, as it is inter-
                  preted immediately, before any  parsing  is  done.   It  has  no
                  effect in non-interactive shells.
    
           noglob Filename  generation  (globbing)  is not performed on any of the
                  words.
                  tional parameters instead of the words.
    
                  More than one parameter name  can  appear  before  the  list  of
                  words.  If N names are given, then on each execution of the loop
                  the next N words are assigned to the  corresponding  parameters.
                  If  there  are  more  names  than remaining words, the remaining
                  parameters are each set to the empty string.  Execution  of  the
                  loop ends when there is no remaining word to assign to the first
                  name.  It is only possible for in to appear as the first name in
                  the  list,  else  it  will  be treated as marking the end of the
                  list.
    
           for (( [expr1] ; [expr2] ; [expr3] )) do list done
                  The arithmetic expression expr1 is evaluated first (see the sec-
                  tion  'Arithmetic Evaluation').  The arithmetic expression expr2
                  is repeatedly evaluated until it  evaluates  to  zero  and  when
                  non-zero,  list  is executed and the arithmetic expression expr3
                  evaluated.  If any expression is omitted, then it behaves as  if
                  it evaluated to 1.
    
           while list do list done
                  Execute  the  do  list  as long as the while list returns a zero
                  exit status.
    
           until list do list done
                  Execute the do list as long as until list returns a nonzero exit
                  status.
    
           repeat word do list done
                  word  is expanded and treated as an arithmetic expression, which
                  must evaluate to a number n.  list is then executed n times.
    
                  The repeat syntax is disabled by default when the  shell  starts
                  in  a  mode emulating another shell.  It can be enabled with the
                  command 'enable -r repeat'
    
           case word in [ [(] pattern [ | pattern ] ... ) list  (;;|;&|;|)  ]  ...
           esac
                  Execute the list associated with the first pattern that  matches
                  word, if any.  The form of the patterns is the same as that used
                  for filename generation.  See the section 'Filename Generation'.
    
                  If  the  list that is executed is terminated with ;& rather than
                  ;;, the following list is also executed.  The rule for the  ter-
                  minator of the following list ;;, ;& or ;| is applied unless the
                  esac is reached.
    
                  If the list that is executed is terminated  with  ;|  the  shell
                  continues  to scan the patterns looking for the next match, exe-
                  cuting the corresponding list, and applying  the  rule  for  the
                  corresponding  terminator  ;;,  ;& or ;|.  Note that word is not
                  re-expanded; all applicable patterns are tested  with  the  same
                  tion until a break or end-of-file is encountered.
    
           ( list )
                  Execute list in a subshell.  Traps set by the trap  builtin  are
                  reset to their default values while executing list.
    
           { list }
                  Execute list.
    
           { try-list } always { always-list }
                  First  execute  try-list.   Regardless of errors, or break, con-
                  tinue, or return commands encountered within  try-list,  execute
                  always-list.   Execution  then  continues from the result of the
                  execution of try-list; in other words, any error, or break, con-
                  tinue,  or  return  command  is treated in the normal way, as if
                  always-list were not  present.   The  two  chunks  of  code  are
                  referred to as the 'try block' and the 'always block'.
    
                  Optional  newlines  or  semicolons  may appear after the always;
                  note, however, that they may not appear  between  the  preceding
                  closing brace and the always.
    
                  An 'error' in this context is a condition such as a syntax error
                  which causes the shell to abort execution of the  current  func-
                  tion,  script,  or  list.   Syntax  errors encountered while the
                  shell is parsing the code do not cause  the  always-list  to  be
                  executed.   For  example, an erroneously constructed if block in
                  try-list would cause the shell to abort during parsing, so  that
                  always-list  would not be executed, while an erroneous substitu-
                  tion such as ${*foo*} would cause a run-time error, after  which
                  always-list would be executed.
    
                  An  error  condition  can  be  tested and reset with the special
                  integer variable TRY_BLOCK_ERROR.  Outside  an  always-list  the
                  value  is  irrelevant,  but  it  is  initialised  to -1.  Inside
                  always-list, the  value  is  1  if  an  error  occurred  in  the
                  try-list,  else  0.   If  TRY_BLOCK_ERROR is set to 0 during the
                  always-list, the error  condition  caused  by  the  try-list  is
                  reset,  and  shell execution continues normally after the end of
                  always-list.  Altering the value during the try-list is not use-
                  ful (unless this forms part of an enclosing always block).
    
                  Regardless  of TRY_BLOCK_ERROR, after the end of always-list the
                  normal shell status $? is the value returned  from  always-list.
                  This   will   be  non-zero  if  there  was  an  error,  even  if
                  TRY_BLOCK_ERROR was set to zero.
    
                  The following executes the given code, ignoring  any  errors  it
                  causes.   This is an alternative to the usual convention of pro-
                  tecting code by executing it in a subshell.
    
                         {
    
           word ... () [ term ] command
                  where term is one or more newline or ;.  Define a function which
                  is referenced by any one of word.  Normally, only  one  word  is
                  provided;  multiple  words  are  usually only useful for setting
                  traps.  The body of the function is the list between the  {  and
                  }.  See the section 'Functions'.
    
                  If  the  option  SH_GLOB  is  set  for  compatibility with other
                  shells, then whitespace may appear between between the left  and
                  right  parentheses  when there is a single word;  otherwise, the
                  parentheses will be treated as forming  a  globbing  pattern  in
                  that case.
    
           time [ pipeline ]
                  The  pipeline is executed, and timing statistics are reported on
                  the standard error in the form specified by the TIMEFMT  parame-
                  ter.   If  pipeline is omitted, print statistics about the shell
                  process and its children.
    
           [[ exp ]]
                  Evaluates the conditional expression exp and return a zero  exit
                  status if it is true.  See the section 'Conditional Expressions'
                  for a description of exp.
    
    
    

    ALTERNATE FORMS FOR COMPLEX COMMANDS

           Many of  zsh's  complex  commands  have  alternate  forms.   These  are
           non-standard  and  are  likely not to be obvious even to seasoned shell
           programmers; they should not be used anywhere that portability of shell
           code is a concern.
    
           The short versions below only work if sublist is of the form '{ list }'
           or if the SHORT_LOOPS option is set.  For the if, while and until  com-
           mands, in both these cases the test part of the loop must also be suit-
           ably delimited, such as by '[[ ... ]]' or '(( ... ))', else the end  of
           the  test will not be recognized.  For the for, repeat, case and select
           commands no such special form for the arguments is necessary,  but  the
           other  condition (the special form of sublist or use of the SHORT_LOOPS
           option) still applies.
    
           if list { list } [ elif list { list } ] ... [ else { list } ]
                  An alternate form of if.  The rules mean that
    
                         if [[ -o ignorebraces ]] {
                           print yes
                         }
    
                  works, but
    
                         if true {  # Does not work!
                           print yes
                         }
    
                  A short form of the arithmetic for command.
    
           foreach name ... ( word ... ) list end
                  Another form of for.
    
           while list { list }
                  An alternative form of while.  Note the limitations on the  form
                  of list mentioned above.
    
           until list { list }
                  An  alternative form of until.  Note the limitations on the form
                  of list mentioned above.
    
           repeat word sublist
                  This is a short form of repeat.
    
           case word { [ [(] pattern [ | pattern ] ... ) list (;;|;&|;|) ] ... }
                  An alternative form of case.
    
           select name [ in word term ] sublist
                  where term is at least one  newline  or  ;.   A  short  form  of
                  select.
    
    
    

    RESERVED WORDS

           The  following  words are recognized as reserved words when used as the
           first word of a command unless quoted or disabled using disable -r:
    
           do done esac then elif else fi for case if while function  repeat  time
           until select coproc nocorrect foreach end ! [[ { }
    
           Additionally,  '}'  is  recognized  in  any  position  if  neither  the
           IGNORE_BRACES option nor the IGNORE_CLOSE_BRACES option is set.
    
    
    

    COMMENTS

           In non-interactive shells, or in interactive shells with  the  INTERAC-
           TIVE_COMMENTS  option set, a word beginning with the third character of
           the histchars parameter ('#' by default) causes that word and  all  the
           following characters up to a newline to be ignored.
    
    
    

    ALIASING

           Every  token  in the shell input is checked to see if there is an alias
           defined for it.  If so, it is replaced by the text of the alias  if  it
           is  in command position (if it could be the first word of a simple com-
           mand), or if the alias is global.  If the text ends with a  space,  the
           next  word  in  the shell input is treated as though it were in command
           position for purposes of alias expansion.  An alias  is  defined  using
           the alias builtin; global aliases may be defined using the -g option to
           that builtin.
    
           Alias expansion is done on the shell input before any  other  expansion
           except  history  expansion.   Therefore, if an alias is defined for the
           word foo, alias expansion may be avoided by quoting part of  the  word,
           entire  line  is read in one go, so that when echobar is executed it is
           too late to expand the newly defined alias.  This is often a problem in
           shell scripts, functions, and code executed with 'source' or '.'.  Con-
           sequently, use of functions  rather  than  aliases  is  recommended  in
           non-interactive code.
    
           Note  also  the  unhelpful  interaction of aliases and function defini-
           tions:
    
                  alias func='noglob func'
                  func() {
                      echo Do something with $*
                  }
    
           Because aliases are expanded in function definitions, this  causes  the
           following command to be executed:
    
                  noglob func() {
                      echo Do something with $*
                  }
    
           which  defines noglob as well as func as functions with the body given.
           To avoid this, either quote the name func or use the alternative  func-
           tion  definition  form  'function func'.  Ensuring the alias is defined
           after the function works but is problematic if the code fragment  might
           be re-executed.
    
    
    

    QUOTING

           A  character  may be quoted (that is, made to stand for itself) by pre-
           ceding it with a '\'.  '\' followed by a newline is ignored.
    
           A string enclosed between '$'' and ''' is processed the same way as the
           string arguments of the print builtin, and the resulting string is con-
           sidered to be entirely quoted.  A literal ''' character can be included
           in the string by using the '\'' escape.
    
           All  characters  enclosed  between a pair of single quotes ('') that is
           not preceded by a '$' are quoted.  A single quote cannot appear  within
           single  quotes unless the option RC_QUOTES is set, in which case a pair
           of single quotes are turned into a single quote.  For example,
    
                  print ''''
    
           outputs nothing apart from a newline if RC_QUOTES is not set,  but  one
           single quote if it is set.
    
           Inside  double  quotes  (""), parameter and command substitution occur,
           and '\' quotes the characters '\', ''', '"', and '$'.
    
    
    

    REDIRECTION

           If a command is followed by & and job control is not active,  then  the
                  Open file word for reading and writing as  standard  input.   If
                  the file does not exist then it is created.
    
           > word Open file word for writing as standard output.  If the file does
                  not exist then it is created.  If the file exists, and the CLOB-
                  BER  option  is  unset,  this  causes an error; otherwise, it is
                  truncated to zero length.
    
           >| word
           >! word
                  Same as >, except that the file is truncated to zero  length  if
                  it exists, even if CLOBBER is unset.
    
           >> word
                  Open  file  word  for writing in append mode as standard output.
                  If the file does not exist, and the  CLOBBER  option  is  unset,
                  this causes an error; otherwise, the file is created.
    
           >>| word
           >>! word
                  Same  as  >>,  except  that  the  file is created if it does not
                  exist, even if CLOBBER is unset.
    
           <<[-] word
                  The shell input is read up to a line that is the same  as  word,
                  or to an end-of-file.  No parameter expansion, command substitu-
                  tion or filename generation is performed on word.  The resulting
                  document, called a here-document, becomes the standard input.
    
                  If  any character of word is quoted with single or double quotes
                  or a '\', no interpretation is placed upon the characters of the
                  document.  Otherwise, parameter and command substitution occurs,
                  '\' followed by a newline is removed, and '\' must  be  used  to
                  quote  the  characters  '\', '$', ''' and the first character of
                  word.
    
                  Note that word itself does not undergo shell  expansion.   Back-
                  quotes  in  word  do  not  have their usual effect; instead they
                  behave similarly to double quotes, except  that  the  backquotes
                  themselves  are  passed through unchanged.  (This information is
                  given for completeness and it is not recommended that backquotes
                  be  used.)  Quotes in the form $'...' have their standard effect
                  of expanding backslashed references to special characters.
    
                  If <<- is used, then all leading tabs are stripped from word and
                  from the document.
    
           <<< word
                  Perform  shell expansion on word and pass the result to standard
                  input.  This is known as a here-string.  Compare the use of word
                  in  here-documents  above,  where  word  does  not undergo shell
                  expansion.
    
           &> word
                  (Except where '>& word' matches one of the above syntaxes;  '&>'
                  can  always  be  used  to avoid this ambiguity.)  Redirects both
                  standard output and standard error (file descriptor  2)  in  the
                  manner  of  '>  word'.   Note  that  this does not have the same
                  effect as '> word 2>&1' in the presence of multios (see the sec-
                  tion below).
    
           >&| word
           >&! word
           &>| word
           &>! word
                  Redirects both standard output and standard error (file descrip-
                  tor 2) in the manner of '>| word'.
    
           >>& word
           &>> word
                  Redirects both standard output and standard error (file descrip-
                  tor 2) in the manner of '>> word'.
    
           >>&| word
           >>&! word
           &>>| word
           &>>! word
                  Redirects both standard output and standard error (file descrip-
                  tor 2) in the manner of '>>| word'.
    
           If one of the above is preceded by a digit, then  the  file  descriptor
           referred  to is that specified by the digit instead of the default 0 or
           1.  The order in which redirections are specified is significant.   The
           shell  evaluates  each  redirection  in  terms of the (file descriptor,
           file) association at the time of evaluation.  For example:
    
                  ... 1>fname 2>&1
    
           first associates file descriptor 1 with file fname.  It then associates
           file descriptor 2 with the file associated with file descriptor 1 (that
           is, fname).  If the order of redirections were reversed, file  descrip-
           tor 2 would be associated with the terminal (assuming file descriptor 1
           had been) and then file descriptor 1  would  be  associated  with  file
           fname.
    
           The  '|&' command separator described in Simple Commands & Pipelines in
           zshmisc(1) is a shorthand for '2>&1 |'.
    
           The various forms of process substitution, '<(list)',  and  '=(list())'
           for  input and '>(list)' for output, are often used together with redi-
           rection.  For example, if word in an output redirection is of the  form
           '>(list)'  then the output is piped to the command represented by list.
           See Process Substitution in zshexpn(1).
    
    
    

    OPENING FILE DESCRIPTORS USING PARAMETERS

    
           The  syntax  {varid}>&-,  for example {myfd}>&-, may be used to close a
           file descriptor opened in this fashion.  Note that the parameter  given
           by varid must previously be set to a file descriptor in this case.
    
           It  is an error to open or close a file descriptor in this fashion when
           the parameter is readonly.  However, it is not  an  error  to  read  or
           write  a  file  descriptor using <&$param or >&$param if param is read-
           only.
    
           If the option CLOBBER is unset, it is an error to open a file  descrip-
           tor  using  a  parameter that is already set to an open file descriptor
           previously allocated by this mechanism.  Unsetting the parameter before
           using it for allocating a file descriptor avoids the error.
    
           Note  that this mechanism merely allocates or closes a file descriptor;
           it does not perform any redirections from or to it.  It is usually con-
           venient  to  allocate  a file descriptor prior to use as an argument to
           exec.  The syntax does not in any case work when  used  around  complex
           commands  such  as  parenthesised subshells or loops, where the opening
           brace is interpreted as part of a command list to be  executed  in  the
           current shell.
    
           The  following shows a typical sequence of allocation, use, and closing
           of a file descriptor:
    
                  integer myfd
                  exec {myfd}>~/logs/mylogfile.txt
                  print This is a log message. >&$myfd
                  exec {myfd}>&-
    
           Note that the expansion of  the  variable  in  the  expression  >&$myfd
           occurs  at  the  point  the  redirection  is opened.  This is after the
           expansion of command arguments and after any redirections to  the  left
           on the command line have been processed.
    
    
    

    MULTIOS

           If the user tries to open a file descriptor for writing more than once,
           the shell opens the file descriptor as a pipe to a process that  copies
           its  input  to  all the specified outputs, similar to tee, provided the
           MULTIOS option is set, as it is by default.  Thus:
    
                  date >foo >bar
    
           writes the date to two files, named 'foo' and 'bar'.  Note that a  pipe
           is an implicit redirection; thus
    
                  date >foo | cat
    
           writes the date to the file 'foo', and also pipes it to cat.
    
           If  the MULTIOS option is set, the word after a redirection operator is
    
                  sort <foo <fubar
    
           or even
    
                  sort <f{oo,ubar}
    
           is equivalent to 'cat foo fubar | sort'.
    
           Expansion  of the redirection argument occurs at the point the redirec-
           tion is opened, at the point described above for the expansion  of  the
           variable in >&$myfd.
    
           Note that a pipe is an implicit redirection; thus
    
                  cat bar | sort <foo
    
           is equivalent to 'cat bar foo | sort' (note the order of the inputs).
    
           If  the MULTIOS option is unset, each redirection replaces the previous
           redirection for that file descriptor.  However, all files redirected to
           are actually opened, so
    
                  echo foo > bar > baz
    
           when MULTIOS is unset will truncate bar, and write 'foo' into baz.
    
           There  is  a  problem  when an output multio is attached to an external
           program.  A simple example shows this:
    
                  cat file >file1 >file2
                  cat file1 file2
    
           Here, it is possible that the second 'cat' will not  display  the  full
           contents  of  file1  and  file2  (i.e.  the  original  contents of file
           repeated twice).
    
           The reason for this is that the multios are spawned after the cat  pro-
           cess is forked from the parent shell, so the parent shell does not wait
           for the multios to finish writing data.   This  means  the  command  as
           shown  can  exit  before  file1 and file2 are completely written.  As a
           workaround, it is possible to run the cat process as part of a  job  in
           the current shell:
    
                  { cat file } >file >file2
    
           Here, the {...} job will pause to wait for both files to be written.
    
    
    

    REDIRECTIONS WITH NO COMMAND

           When a simple command consists of one or more redirection operators and
           zero or more parameter assignments, but no command name, zsh can behave
           is 'cat' and for READNULLCMD is 'more'. Thus
    
                  < file
    
           shows the contents of file on standard output, with paging if that is a
           terminal.  NULLCMD and READNULLCMD may refer to shell functions.
    
    
    

    COMMAND EXECUTION

           If a command name contains no slashes, the shell attempts to locate it.
           If  there exists a shell function by that name, the function is invoked
           as described in the section  'Functions'.   If  there  exists  a  shell
           builtin by that name, the builtin is invoked.
    
           Otherwise,  the  shell  searches  each element of $path for a directory
           containing an executable file by that name.  If the  search  is  unsuc-
           cessful,  the  shell prints an error message and returns a nonzero exit
           status.
    
           If execution fails because the file is not in  executable  format,  and
           the  file  is  not  a  directory,  it  is assumed to be a shell script.
           /bin/sh is spawned to execute it.  If the program is a  file  beginning
           with '#!', the remainder of the first line specifies an interpreter for
           the program.  The shell will execute the specified interpreter on oper-
           ating  systems that do not handle this executable format in the kernel.
    
           If no external command is found but a  function  command_not_found_han-
           dler  exists  the  shell  executes  this function with all command line
           arguments.  The function should return status zero if  it  successfully
           handled  the  command,  or non-zero status if it failed.  In the latter
           case the standard handling is applied: 'command not found'  is  printed
           to  standard  error and the shell exits with status 127.  Note that the
           handler is executed in a subshell forked to execute  an  external  com-
           mand,  hence  changes  to  directories,  shell parameters, etc. have no
           effect on the main shell.
    
    
    

    FUNCTIONS

           Shell functions are defined with the function reserved word or the spe-
           cial  syntax  'funcname  ()'.   Shell  functions are read in and stored
           internally.  Alias names are resolved when the function is read.  Func-
           tions  are  executed  like  commands with the arguments passed as posi-
           tional parameters.  (See the section 'Command Execution'.)
    
           Functions execute in the same process as the caller and share all files
           and  present  working  directory  with  the caller.  A trap on EXIT set
           inside a function is executed after the function completes in the envi-
           ronment of the caller.
    
           The return builtin is used to return from function calls.
    
           Function  identifiers  can be listed with the functions builtin.  Func-
           tions can be undefined with the unfunction builtin.
           Note  that  for functions precompiled with the zcompile builtin command
           the flag -U must be provided when the .zwc file is created, as the cor-
           responding information is compiled into the latter.
    
           For  each  element  in fpath, the shell looks for three possible files,
           the newest of which is used to load the definition for the function:
    
           element.zwc
                  A file created with  the  zcompile  builtin  command,  which  is
                  expected  to  contain  the  definitions for all functions in the
                  directory named element.  The file is treated in the same manner
                  as  a  directory  containing files for functions and is searched
                  for the definition of the function.   If the definition  is  not
                  found,  the  search for a definition proceeds with the other two
                  possibilities described below.
    
                  If element already includes a .zwc extension (i.e. the extension
                  was  explicitly  given by the user), element is searched for the
                  definition of the function without comparing its age to that  of
                  other  files;  in  fact, there does not need to be any directory
                  named element without the suffix.   Thus  including  an  element
                  such as '/usr/local/funcs.zwc' in fpath will speed up the search
                  for functions, with the  disadvantage  that  functions  included
                  must  be  explicitly recompiled by hand before the shell notices
                  any changes.
    
           element/function.zwc
                  A file created with zcompile, which is expected to  contain  the
                  definition  for function.  It may include other function defini-
                  tions as well, but those are neither loaded nor executed; a file
                  found  in  this way is searched only for the definition of func-
                  tion.
    
           element/function
                  A file of zsh command text, taken to be the definition for func-
                  tion.
    
           In  summary, the order of searching is, first, in the parents of direc-
           tories in fpath for the newer of  either  a  compiled  directory  or  a
           directory  in fpath; second, if more than one of these contains a defi-
           nition for the function that is sought, the leftmost in  the  fpath  is
           chosen;  and  third, within a directory, the newer of either a compiled
           function or an ordinary function definition is used.
    
           If the KSH_AUTOLOAD option is set, or the file contains only  a  simple
           definition of the function, the file's contents will be executed.  This
           will normally define the function in question,  but  may  also  perform
           initialization, which is executed in the context of the function execu-
           tion, and may therefore define local parameters.  It is an error if the
           function is not defined by loading the file.
    
           Otherwise,  the  function body (with no surrounding 'funcname() {...}')
    
           then 'func; func' with KSH_AUTOLOAD set will produce both  messages  on
           the  first  call, but only the message 'This is func' on the second and
           subsequent calls.  Without KSH_AUTOLOAD set, it will produce  the  ini-
           tialization  message  on  the  first call, and the other message on the
           second and subsequent calls.
    
           It is also possible  to  create  a  function  that  is  not  marked  as
           autoloaded,  but  which loads its own definition by searching fpath, by
           using 'autoload -X' within a shell function.  For example, the  follow-
           ing are equivalent:
    
                  myfunc() {
                    autoload -X
                  }
                  myfunc args...
    
           and
    
                  unfunction myfunc   # if myfunc was defined
                  autoload myfunc
                  myfunc args...
    
           In  fact,  the  functions  command outputs 'builtin autoload -X' as the
           body of an autoloaded function.  This is done so that
    
                  eval "$(functions)"
    
           produces a reasonable result.  A true autoloaded function can be  iden-
           tified  by  the  presence  of  the  comment  '# undefined' in the body,
           because all comments are discarded from defined functions.
    
           To load the definition of an autoloaded function myfunc without execut-
           ing myfunc, use:
    
                  autoload +X myfunc
    
    
    

    ANONYMOUS FUNCTIONS

           If  no  name  is given for a function, it is 'anonymous' and is handled
           specially.  Either form of function definition may be used: a '()' with
           no  preceding  name, or a 'function' with an immediately following open
           brace.  The function is executed immediately at the point of definition
           and  is  not  stored  for  future  use.   The  function  name is set to
           '(anon)'.
    
           Arguments to the function may be specified as words following the clos-
           ing  brace  defining the function, hence if there are none no arguments
           (other than $0) are set.  This is a difference from the way other func-
           tions  are  parsed: normal function definitions may be followed by cer-
           tain keywords such as 'else' or 'fi', which will be  treated  as  argu-
           ments  to anonymous functions, so that a newline or semicolon is needed
                  variable=outside
                  function {
                    local variable=inside
                    print "I am $variable with arguments $*"
                  } this and that
                  print "I am $variable"
    
           outputs the following:
    
                  I am inside with arguments this and that
                  I am outside
    
           Note that function definitions with arguments that expand  to  nothing,
           for  example 'name=; function $name { ... }', are not treated as anony-
           mous functions.  Instead, they are treated as normal  function  defini-
           tions where the definition is silently discarded.
    
    
    

    SPECIAL FUNCTIONS

           Certain functions, if defined, have special meaning to the shell.
    
       Hook Functions
           For the functions below, it is possible to define an array that has the
           same name as the function with '_functions' appended.  Any  element  in
           such an array is taken as the name of a function to execute; it is exe-
           cuted in the same context and with the  same  arguments  as  the  basic
           function.   For example, if $chpwd_functions is an array containing the
           values 'mychpwd', 'chpwd_save_dirstack', then  the  shell  attempts  to
           execute  the functions 'chpwd', 'mychpwd' and 'chpwd_save_dirstack', in
           that order.  Any function that does not exist is silently  ignored.   A
           function  found  by  this mechanism is referred to elsewhere as a 'hook
           function'.  An error in any function causes subsequent functions not to
           be  run.  Note further that an error in a precmd hook causes an immedi-
           ately following periodic function not to run (though it may run at  the
           next opportunity).
    
           chpwd  Executed whenever the current working directory is changed.
    
           periodic
                  If  the parameter PERIOD is set, this function is executed every
                  $PERIOD seconds, just before a prompt.  Note  that  if  multiple
                  functions  are  defined  using the array periodic_functions only
                  one period is applied to the complete set of functions, and  the
                  scheduled time is not reset if the list of functions is altered.
                  Hence the set of functions is always called together.
    
           precmd Executed before each prompt.  Note that precommand functions are
                  not  re-executed  simply because the command line is redrawn, as
                  happens, for example, when a notification about an  exiting  job
                  is displayed.
    
                  tory  line  (so  that  any  terminating  newline  will  still be
                  present).
    
                  If any of the hook functions return a non-zero value the history
                  line will not be saved, although it lingers in the history until
                  the next line is executed allow you to reuse or edit it  immedi-
                  ately.
    
                  A  hook function may call 'fc -p ...' to switch the history con-
                  text so that the history is saved in a different file  from  the
                  that  in  the  global  HISTFILE parameter.  This is handled spe-
                  cially: the history context is automatically restored after  the
                  processing of the history line is finished.
    
                  The  following  example  function first adds the history line to
                  the normal history with the newline stripped,  which is  usually
                  the  correct behaviour.  Then it switches the history context so
                  that the line will be written to a history file in  the  current
                  directory.
    
                         zshaddhistory() {
                           print -sr -- ${1%%$'\n'}
                           fc -p .zsh_local_history
                         }
    
           zshexit
                  Executed at the point where the main shell is about to exit nor-
                  mally.  This is not called by exiting subshells,  nor  when  the
                  exec  precommand  modifier  is  used before an external command.
                  Also, unlike TRAPEXIT, it is not called when functions exit.
    
       Trap Functions
           The functions below are treated specially but do not have corresponding
           hook arrays.
    
           TRAPNAL
                  If defined and non-null, this function will be executed whenever
                  the shell catches a signal SIGNAL, where NAL is a signal name as
                  specified  for  the  kill  builtin.   The  signal number will be
                  passed as the first parameter to the function.
    
                  If a function of this form is defined and null,  the  shell  and
                  processes spawned by it will ignore SIGNAL.
    
                  The return status from the function is handled specially.  If it
                  is zero, the signal is assumed to have been handled, and  execu-
                  tion  continues  normally.   Otherwise, the shell will behave as
                  interrupted except  that  the  return  status  of  the  trap  is
                  retained.
    
                  Programs  terminated  by  uncaught  signals typically return the
                  executed before each command; otherwise executed after each com-
                  mand.  See the description of the trap builtin in zshbuiltins(1)
                  for details of additional features provided in debug traps.
    
           TRAPEXIT
                  Executed when the shell exits,  or  when  the  current  function
                  exits  if  defined  inside  a  function.  The value of $? at the
                  start of execution is the exit status of the shell or the return
                  status of the function exiting.
    
           TRAPZERR
                  Executed  whenever  a  command has a non-zero exit status.  How-
                  ever, the function is not executed if the command occurred in  a
                  sublist  followed  by  '&&' or '||'; only the final command in a
                  sublist of this type causes the trap to be executed.  The  func-
                  tion TRAPERR acts the same as TRAPZERR on systems where there is
                  no SIGERR (this is the usual case).
    
           The functions beginning 'TRAP' may alternatively be  defined  with  the
           trap  builtin:   this  may be preferable for some uses.  Setting a trap
           with one form removes any trap of the other form for the  same  signal;
           removing  a  trap in either form removes all traps for the same signal.
           The forms
    
                  TRAPNAL() {
                   # code
                  }
    
           ('function traps') and
    
                  trap '
                   # code
                  ' NAL
    
           ('list traps') are equivalent in most ways, the  exceptions  being  the
           following:
    
           ?      Function  traps  have  all  the  properties of normal functions,
                  appearing in the list of functions and being called  with  their
                  own  function context rather than the context where the trap was
                  triggered.
    
           ?      The return status from function  traps  is  special,  whereas  a
                  return from a list trap causes the surrounding context to return
                  with the given status.
    
           ?      Function traps are not reset  within  subshells,  in  accordance
                  with  zsh  behaviour;  list  traps are reset, in accordance with
                  POSIX behaviour.
    
    
    

    JOBS

           If the MONITOR option is set, an interactive  shell  associates  a  job
           If  you are running a job and wish to do something else you may hit the
           key ^Z (control-Z) which sends a TSTP signal to the current job:   this
           key  may  be redefined by the susp option of the external stty command.
           The shell will then normally indicate  that  the  job  has  been  'sus-
           pended',  and  print another prompt.  You can then manipulate the state
           of this job, putting it in the background with the bg command,  or  run
           some  other  commands  and  then eventually bring the job back into the
           foreground with the foreground command fg.  A ^Z takes  effect  immedi-
           ately  and is like an interrupt in that pending output and unread input
           are discarded when it is typed.
    
           A job being run in the background will suspend if it tries to read from
           the terminal.
    
           Note  that  if  the  job running in the foreground is a shell function,
           then suspending it will have the effect of causing the shell  to  fork.
           This  is  necessary  to  separate the function's state from that of the
           parent shell performing the job control, so that the latter can  return
           to  the  command  line prompt.  As a result, even if fg is used to con-
           tinue the job the function will no longer be part of the parent  shell,
           and any variables set by the function will not be visible in the parent
           shell.  Thus the behaviour is different from the case where  the  func-
           tion  was  never suspended.  Zsh is different from many other shells in
           this regard.
    
           The same behaviour is found when the shell is  executing  code  as  the
           right  hand  side  of a pipeline or any complex shell construct such as
           if, for, etc., in order that the entire block of code can be managed as
           a  single job.  Background jobs are normally allowed to produce output,
           but this can be disabled by giving the command 'stty tostop'.   If  you
           set this tty option, then background jobs will suspend when they try to
           produce output like they do when they try to read input.
    
           When a command is suspended and continued later with  the  fg  or  wait
           builtins,  zsh  restores tty modes that were in effect when it was sus-
           pended.  This (intentionally) does not apply if the command is  contin-
           ued via 'kill -CONT', nor when it is continued with bg.
    
           There  are  several  ways  to refer to jobs in the shell.  A job can be
           referred to by the process ID of any process of the job or  by  one  of
           the following:
    
           %number
                  The job with the given number.
           %string
                  Any job whose command line begins with string.
           %?string
                  Any job whose command line contains string.
           %%     Current job.
           %+     Equivalent to '%%'.
           %-     Previous job.
    
           suspended  jobs will be terminated, and the running jobs will be sent a
           SIGHUP signal, if the HUP option is set.
    
           To avoid having the shell terminate the running jobs,  either  use  the
           nohup command (see nohup(1)) or the disown builtin.
    
    
    

    SIGNALS

           The INT and QUIT signals for an invoked command are ignored if the com-
           mand is followed by '&' and the MONITOR  option  is  not  active.   The
           shell  itself  always ignores the QUIT signal.  Otherwise, signals have
           the values inherited by the shell from its parent (but see the  TRAPNAL
           special functions in the section 'Functions').
    
    
    

    ARITHMETIC EVALUATION

           The  shell  can  perform  integer and floating point arithmetic, either
           using the builtin let, or via a substitution of the form $((...)).  For
           integers,  the  shell is usually compiled to use 8-byte precision where
           this is available, otherwise precision is 4 bytes.  This can be tested,
           for example, by giving the command 'print - $(( 12345678901 ))'; if the
           number appears unchanged, the precision is at least 8 bytes.   Floating
           point  arithmetic  always  uses  the 'double' type with whatever corre-
           sponding precision is provided by the compiler and the library.
    
           The let builtin command takes arithmetic expressions as arguments; each
           is  evaluated  separately.   Since many of the arithmetic operators, as
           well as spaces, require quoting, an alternative form is  provided:  for
           any command which begins with a '((', all the characters until a match-
           ing '))' are treated as a quoted expression  and  arithmetic  expansion
           performed  as  for  an  argument  of let.  More precisely, '((...))' is
           equivalent to 'let "..."'.  The return status is 0  if  the  arithmetic
           value of the expression is non-zero, 1 if it is zero, and 2 if an error
           occurred.
    
           For example, the following statement
    
                  (( val = 2 + 1 ))
    
           is equivalent to
    
                  let "val = 2 + 1"
    
           both assigning the value 3 to the shell variable val  and  returning  a
           zero status.
    
           Integers can be in bases other than 10.  A leading '0x' or '0X' denotes
           hexadecimal.  Integers may also be of the form 'base#n', where base  is
           a decimal number between two and thirty-six representing the arithmetic
           base and n is a number in that base (for example,  '16#ff'  is  255  in
           hexadecimal).   The base# may also be omitted, in which case base 10 is
           used.  For backwards compatibility the form '[base]n' is also accepted.
    
           It is also possible to specify a base to be used for output in the form
    
           outputs first '8#40', the rightmost value in the given output base, and
           then '8#40 16#20', because y has been explicitly declared to have  out-
           put base 16, while x (assuming it does not already exist) is implicitly
           typed by the arithmetic evaluation, where it acquires the  output  base
           8.
    
           If  the  C_BASES  option  is set, hexadecimal numbers in the standard C
           format, for example 0xFF instead of the usual '16#FF'.  If  the  option
           OCTAL_ZEROES  is also set (it is not by default), octal numbers will be
           treated similarly and hence appear as '077' instead  of  '8#77'.   This
           option  has no effect on the output of bases other than hexadecimal and
           octal, and these formats are always understood on input.
    
           When an output base is specified using the '[#base]' syntax, an  appro-
           priate  base prefix will be output if necessary, so that the value out-
           put is valid syntax for input.   If  the  #  is  doubled,  for  example
           '[##16]', then no base prefix is output.
    
           Floating  point  constants  are recognized by the presence of a decimal
           point or an exponent.  The decimal point may be the first character  of
           the  constant, but the exponent character e or E may not, as it will be
           taken for a parameter name.
    
           An arithmetic expression uses nearly the same syntax and  associativity
           of expressions as in C.
    
           In  the native mode of operation, the following operators are supported
           (listed in decreasing order of precedence):
    
           + - ! ~ ++ --
                  unary plus/minus, logical NOT, complement, {pre,post}{in,de}cre-
                  ment
           << >>  bitwise shift left, right
           &      bitwise AND
           ^      bitwise XOR
           |      bitwise OR
           **     exponentiation
           * / %  multiplication, division, modulus (remainder)
           + -    addition, subtraction
           < > <= >=
                  comparison
           == !=  equality and inequality
           &&     logical AND
           || ^^  logical OR, XOR
           ? :    ternary operator
           = += -= *= /= %= &= ^= |= <<= >>= &&= ||= ^^= **=
                  assignment
           ,      comma operator
    
           The  operators  '&&',  '||', '&&=', and '||=' are short-circuiting, and
           only one of the latter two expressions in a ternary operator is  evalu-
                  comparison
           == !=  equality and inequality
           &      bitwise AND
           ^      bitwise XOR
           |      bitwise OR
           &&     logical AND
           ^^     logical XOR
           ||     logical OR
           ? :    ternary operator
           = += -= *= /= %= &= ^= |= <<= >>= &&= ||= ^^= **=
                  assignment
           ,      comma operator
    
           Note the precedence of exponentiation in both cases is  below  that  of
           unary operators, hence '-3**2' evaluates as '9', not -9.  Use parenthe-
           ses where necessary: '-(3**2)'.  This is for compatibility  with  other
           shells.
    
           Mathematical  functions  can  be  called  with the syntax 'func(args)',
           where the function decides if the  args  is  used  as  a  string  or  a
           comma-separated  list  of  arithmetic  expressions. The shell currently
           defines no mathematical functions by default, but the module  zsh/math-
           func may be loaded with the zmodload builtin to provide standard float-
           ing point mathematical functions.
    
           An expression of the form '##x' where x is any character sequence  such
           as  'a',  '^A',  or  '\M-\C-x' gives the value of this character and an
           expression of the form '#foo' gives the value of the first character of
           the  contents  of the parameter foo.  Character values are according to
           the character set used in the current locale; for  multibyte  character
           handling the option MULTIBYTE must be set.  Note that this form is dif-
           ferent from '$#foo', a standard parameter substitution which gives  the
           length of the parameter foo.  '#\' is accepted instead of '##', but its
           use is deprecated.
    
           Named parameters and subscripted  arrays  can  be  referenced  by  name
           within  an  arithmetic expression without using the parameter expansion
           syntax.  For example,
    
                  ((val2 = val1 * 2))
    
           assigns twice the value of $val1 to the parameter named val2.
    
           An internal integer representation of a named parameter can  be  speci-
           fied  with  the integer builtin.  Arithmetic evaluation is performed on
           the value of each assignment to a named parameter declared  integer  in
           this  manner.   Assigning a floating point number to an integer results
           in rounding down to the next integer.
    
           Likewise, floating  point  numbers  can  be  declared  with  the  float
           builtin; there are two types, differing only in their output format, as
           described for the typeset builtin.  The output format can  be  bypassed
           being  declared,  it  will  be implicitly typed as integer or float and
           retain that type either until the type is explicitly changed  or  until
           the  end  of  the  scope.   This can have unforeseen consequences.  For
           example, in the loop
    
                  for (( f = 0; f < 1; f += 0.1 )); do
                  # use $f
                  done
    
           if f has not already been declared, the first assignment will cause  it
           to  be created as an integer, and consequently the operation 'f += 0.1'
           will always cause the result to be truncated to zero, so that the  loop
           will  fail.  A simple fix would be to turn the initialization into 'f =
           0.0'.  It is therefore best to declare numeric variables with  explicit
           types.
    
    
    

    CONDITIONAL EXPRESSIONS

           A  conditional  expression is used with the [[ compound command to test
           attributes of files and to compare strings.   Each  expression  can  be
           constructed  from  one or more of the following unary or binary expres-
           sions:
    
           -a file
                  true if file exists.
    
           -b file
                  true if file exists and is a block special file.
    
           -c file
                  true if file exists and is a character special file.
    
           -d file
                  true if file exists and is a directory.
    
           -e file
                  true if file exists.
    
           -f file
                  true if file exists and is a regular file.
    
           -g file
                  true if file exists and has its setgid bit set.
    
           -h file
                  true if file exists and is a symbolic link.
    
           -k file
                  true if file exists and has its sticky bit set.
    
           -n string
                  true if length of string is non-zero.
    
           -t fd  true if file descriptor number fd is open and associated with  a
                  terminal device.  (note: fd is not optional)
    
           -u file
                  true if file exists and has its setuid bit set.
    
           -w file
                  true if file exists and is writable by current process.
    
           -x file
                  true  if  file  exists and is executable by current process.  If
                  file exists and is a directory, then  the  current  process  has
                  permission to search in the directory.
    
           -z string
                  true if length of string is zero.
    
           -L file
                  true if file exists and is a symbolic link.
    
           -O file
                  true  if  file  exists  and is owned by the effective user ID of
                  this process.
    
           -G file
                  true if file exists and its group matches the effective group ID
                  of this process.
    
           -S file
                  true if file exists and is a socket.
    
           -N file
                  true  if  file  exists and its access time is not newer than its
                  modification time.
    
           file1 -nt file2
                  true if file1 exists and is newer than file2.
    
           file1 -ot file2
                  true if file1 exists and is older than file2.
    
           file1 -ef file2
                  true if file1 and file2 exist and refer to the same file.
    
           string = pattern
           string == pattern
                  true if string matches pattern.  The '==' form is the  preferred
                  one.   The  '=' form is for backward compatibility and should be
                  considered obsolete.
    
           string != pattern
                  true if string does not match pattern.
                  is identical to '$MATCH'.  The setting of the option  KSH_ARRAYS
                  is  respected.   Likewise,  the  array  match is set to the sub-
                  strings that matched parenthesised subexpressions and the arrays
                  mbegin  and  mend to the indices of the start and end positions,
                  respectively, of the substrings within string.  The  arrays  are
                  not  set  if  there  were no parenthesised subexpresssions.  For
                  example, if the string 'a short string' is matched  against  the
                  regular   expression   's(...)t',   then  (assuming  the  option
                  KSH_ARRAYS is not set) MATCH, MBEGIN and MEND are 'short', 3 and
                  7,  respectively,  while match, mbegin and mend are single entry
                  arrays containing the strings 'hor', '4' and '6, respectively.
    
                  If the option BASH_REMATCH is set the array BASH_REMATCH is  set
                  to  the  substring that matched the pattern followed by the sub-
                  strings that matched  parenthesised  subexpressions  within  the
                  pattern.
    
           string1 < string2
                  true  if  string1  comes  before string2 based on ASCII value of
                  their characters.
    
           string1 > string2
                  true if string1 comes after string2  based  on  ASCII  value  of
                  their characters.
    
           exp1 -eq exp2
                  true if exp1 is numerically equal to exp2.
    
           exp1 -ne exp2
                  true if exp1 is numerically not equal to exp2.
    
           exp1 -lt exp2
                  true if exp1 is numerically less than exp2.
    
           exp1 -gt exp2
                  true if exp1 is numerically greater than exp2.
    
           exp1 -le exp2
                  true if exp1 is numerically less than or equal to exp2.
    
           exp1 -ge exp2
                  true if exp1 is numerically greater than or equal to exp2.
    
           ( exp )
                  true if exp is true.
    
           ! exp  true if exp is false.
    
           exp1 && exp2
                  true if exp1 and exp2 are both true.
    
           exp1 || exp2
           the /dev/fd directory.
    
           In  the  forms which do numeric comparison, the expressions exp undergo
           arithmetic expansion as if they were enclosed in $((...)).
    
           For example, the following:
    
                  [[ ( -f foo || -f bar ) && $report = y* ]] && print File exists.
    
           tests if either file foo or file bar exists, and if so, if the value of
           the  parameter  report  begins  with  'y'; if the complete condition is
           true, the message 'File exists.' is printed.
    
    
    

    EXPANSION OF PROMPT SEQUENCES

           Prompt sequences undergo a special form of  expansion.   This  type  of
           expansion is also available using the -P option to the print builtin.
    
           If the PROMPT_SUBST option is set, the prompt string is first subjected
           to parameter expansion, command substitution and arithmetic  expansion.
           See zshexpn(1).
    
           Certain escape sequences may be recognised in the prompt string.
    
           If  the  PROMPT_BANG  option is set, a '!' in the prompt is replaced by
           the current history event number.  A literal '!'  may  then  be  repre-
           sented as '!!'.
    
           If  the  PROMPT_PERCENT  option  is  set, certain escape sequences that
           start with '%' are expanded.  Many escapes are  followed  by  a  single
           character,  although  some  of  these take an optional integer argument
           that should appear between the  '%'  and  the  next  character  of  the
           sequence.   More  complicated escape sequences are available to provide
           conditional expansion.
    
    
    

    SIMPLE PROMPT ESCAPES

       Special characters
           %%     A '%'.
    
           %)     A ')'.
    
       Login information
           %l     The line (tty) the user is logged in on, without '/dev/' prefix.
                  If the name starts with '/dev/tty', that prefix is stripped.
    
           %M     The full machine hostname.
    
           %m     The hostname up to the first '.'.  An integer may follow the '%'
                  to specify how many components  of  the  hostname  are  desired.
                  With a negative integer, trailing components of the hostname are
                  shown.
    
           %?     The return status of the last command executed just  before  the
                  prompt.
    
           %_     The  status  of the parser, i.e. the shell constructs (like 'if'
                  and 'for') that have been started on the command line. If  given
                  an  integer  number  that  many strings will be printed; zero or
                  negative or no integer means print as many as there  are.   This
                  is most useful in prompts PS2 for continuation lines and PS4 for
                  debugging with the XTRACE option; in the  latter  case  it  will
                  also work non-interactively.
    
           %d
           /      Current  working  directory.   If an integer follows the '%', it
                  specifies a number of trailing components of the current working
                  directory  to show; zero means the whole path.  A negative inte-
                  ger specifies leading components, i.e. %-1d specifies the  first
                  component.
    
           %~     As  %d  and %/, but if the current working directory has a named
                  directory as its prefix, that part is replaced by a '~' followed
                  by  the  name  of  the directory.  If it starts with $HOME, that
                  part is replaced by a '~'.
    
           %h
           %!     Current history event number.
    
           %i     The line number currently being executed in the script,  sourced
                  file,  or  shell  function given by %N.  This is most useful for
                  debugging as part of $PS4.
    
           %I     The line number currently being executed in the file  %x.   This
                  is similar to %i, but the line number is always a line number in
                  the file where the code was defined, even if the code is a shell
                  function.
    
           %j     The number of jobs.
    
           %L     The current value of $SHLVL.
    
           %N     The name of the script, sourced file, or shell function that zsh
                  is currently executing, whichever was started most recently.  If
                  there is none, this is equivalent to the parameter $0.  An inte-
                  ger may follow the '%' to specify a number of trailing path com-
                  ponents  to  show; zero means the full path.  A negative integer
                  specifies leading components.
    
           %x     The name of the file containing the source code currently  being
                  executed.  This behaves as %N except that function and eval com-
                  mand names are not shown,  instead  the  file  where  they  were
                  defined.
    
    
           %t
           %@     Current time of day, in 12-hour, am/pm format.
    
           %*     Current time of day in 24-hour format, with seconds.
    
           %w     The date in day-dd format.
    
           %W     The date in mm/dd/yy format.
    
           %D{string}
                  string is formatted using  the  strftime  function.   See  strf-
                  time(3)  for  more details.  Various zsh extensions provide num-
                  bers with no leading zero or space if the  number  is  a  single
                  digit:
    
                  %f     a day of the month
                  %K     the hour of the day on the 24-hour clock
                  %L     the hour of the day on the 12-hour clock
    
                  The  GNU extension that a '-' between the % and the format char-
                  acter causes a leading zero or space to be stripped  is  handled
                  directly  by  the shell for the format characters d, f, H, k, l,
                  m, M, S and y; any other format characters are provided to strf-
                  time()  with any leading '-', present, so the handling is system
                  dependent.  Further GNU extensions are not supported at present.
    
       Visual effects
           %B (%b)
                  Start (stop) boldface mode.
    
           %E     Clear to end of line.
    
           %U (%u)
                  Start (stop) underline mode.
    
           %S (%s)
                  Start (stop) standout mode.
    
           %F (%f)
                  Start  (stop)  using a different foreground colour, if supported
                  by the terminal.  The colour may be specified two  ways:  either
                  as  a  numeric  argument,  as normal, or by a sequence in braces
                  following the %F, for example %F{red}.  In the latter  case  the
                  values  allowed  are  as  described  for  the  fg  zle_highlight
                  attribute; see Character Highlighting in zshzle(1).  This  means
                  that numeric colours are allowed in the second format also.
    
           %K (%k)
                  Start (stop) using a different bacKground colour.  The syntax is
                  identical to that for %F and %f.
                  within a %{...%} sequence together with the  appropriate  number
                  of  %G  sequences  to  indicate  the  correct width.  An integer
                  between the '%' and 'G' indicates a character width  other  than
                  one.   Hence  %{seq%2G%} outputs seq and assumes it takes up the
                  width of two standard characters.
    
                  Multiple uses of %G accumulate in the obvious fashion; the posi-
                  tion  of  the %G is unimportant.  Negative integers are not han-
                  dled.
    
                  Note that when prompt truncation is in use it  is  advisable  to
                  divide  up  output  into  single  characters within each %{...%}
                  group so that the correct truncation point can be found.
    
    
    

    CONDITIONAL SUBSTRINGS IN PROMPTS

           %v     The value of the first element of  the  psvar  array  parameter.
                  Following  the  '%'  with  an  integer gives that element of the
                  array.  Negative integers count from the end of the array.
    
           %(x.true-text.false-text)
                  Specifies a ternary expression.  The character following  the  x
                  is  arbitrary;  the  same character is used to separate the text
                  for the 'true' result from that for the  'false'  result.   This
                  separator  may  not appear in the true-text, except as part of a
                  %-escape sequence.  A ')' may appear in the false-text as  '%)'.
                  true-text  and  false-text  may  both contain arbitrarily-nested
                  escape sequences, including further ternary expressions.
    
                  The left parenthesis may be preceded or followed by  a  positive
                  integer  n,  which defaults to zero.  A negative integer will be
                  multiplied by -1.  The test character x may be any of  the  fol-
                  lowing:
    
                  !      True if the shell is running with privileges.
                  #      True if the effective uid of the current process is n.
                  ?      True if the exit status of the last command was n.
                  _      True if at least n shell constructs were started.
                  C
                  /      True if the current absolute path has at least n elements
                         relative to the root directory, hence / is counted  as  0
                         elements.
                  c
                  .
                  ~      True if the current path, with prefix replacement, has at
                         least n elements relative to the root directory, hence  /
                         is counted as 0 elements.
                  D      True if the month is equal to n (January = 0).
                  d      True if the day of the month is equal to n.
                  g      True if the effective gid of the current process is n.
                  j      True if the number of jobs is at least n.
                  L      True if the SHLVL parameter is at least n.
                  string.   The  third,  deprecated,   form   is   equivalent   to
                  '%xstringx',  i.e.  x  may be '<' or '>'.  The numeric argument,
                  which in the third form may appear immediately  after  the  '[',
                  specifies  the  maximum  permitted length of the various strings
                  that can be displayed in the prompt.  The string  will  be  dis-
                  played  in  place  of  the truncated portion of any string; note
                  this does not undergo prompt expansion.
    
                  The forms with '<' truncate at the left of the string,  and  the
                  forms  with  '>' truncate at the right of the string.  For exam-
                  ple, if  the  current  directory  is  '/home/pike',  the  prompt
                  '%8<..<%/'  will expand to '..e/pike'.  In this string, the ter-
                  minating character ('<', '>' or ']'), or in fact any  character,
                  may be quoted by a preceding '\'; note when using print -P, how-
                  ever, that this must be doubled as the string is also subject to
                  standard  print  processing,  in  addition  to  any  backslashes
                  removed by a double quoted string:  the worst case is  therefore
                  'print -P "%<\\\\<<..."'.
    
                  If the string is longer than the specified truncation length, it
                  will appear in full, completely replacing the truncated  string.
    
                  The part of the prompt string to be truncated runs to the end of
                  the string, or to the end of the next  enclosing  group  of  the
                  '%('  construct,  or  to  the next truncation encountered at the
                  same grouping level (i.e. truncations inside a  '%('  are  sepa-
                  rate), which ever comes first.  In particular, a truncation with
                  argument zero (e.g. '%<<') marks the end of  the  range  of  the
                  string  to  be truncated while turning off truncation from there
                  on. For example, the prompt  '%10<...<%~%<<%#  '  will  print  a
                  truncated representation of the current directory, followed by a
                  '%' or '#', followed by a space.  Without the '%<<',  those  two
                  characters would be included in the string to be truncated.
    
    
    

    zsh 4.3.17 February 22, 2011 ZSHMISC(1)

    
    
  • MORE RESOURCE


  • Linux

    The Distributions





    Linux

    The Software





    Linux

    The News



  • MARKETING






  • Toll Free

webmaster@linuxguruz.com
Copyright © 1999 - 2016 by LinuxGuruz