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           chmod [OPTION]... MODE[,MODE]... FILE...
           chmod [OPTION]... OCTAL-MODE FILE...
           chmod [OPTION]... --reference=RFILE FILE...


           This manual page documents the GNU version of chmod.  chmod changes the
           file mode bits of each given file  according  to  mode,  which  can  be
           either a symbolic representation of changes to make, or an octal number
           representing the bit pattern for the new mode bits.
           The format of a symbolic mode is  [ugoa...][[+-=][perms...]...],  where
           perms  is  either zero or more letters from the set rwxXst, or a single
           letter from the set ugo.  Multiple symbolic modes can be  given,  sepa-
           rated by commas.
           A  combination  of the letters ugoa controls which users' access to the
           file will be changed: the user who owns it  (u),  other  users  in  the
           file's group (g), other users not in the file's group (o), or all users
           (a).  If none of these are given, the effect is as if a were given, but
           bits that are set in the umask are not affected.
           The  operator  +  causes the selected file mode bits to be added to the
           existing file mode bits of each file; - causes them to be removed;  and
           =  causes  them  to  be added and causes unmentioned bits to be removed
           except that a directory's unmentioned set user and group  ID  bits  are
           not affected.
           The  letters  rwxXst select file mode bits for the affected users: read
           (r), write (w), execute (or search for directories) (x), execute/search
           only  if  the file is a directory or already has execute permission for
           some user (X), set user or group ID on execution (s), restricted  dele-
           tion  flag or sticky bit (t).  Instead of one or more of these letters,
           you can specify exactly one of the letters ugo: the permissions granted
           to  the  user  who  owns the file (u), the permissions granted to other
           users who are members of the file's  group  (g),  and  the  permissions
           granted  to  users  that are in neither of the two preceding categories
           A numeric mode is from one to  four  octal  digits  (0-7),  derived  by
           adding up the bits with values 4, 2, and 1.  Omitted digits are assumed
           to be leading zeros.  The first digit selects the set user ID  (4)  and
           set group ID (2) and restricted deletion or sticky (1) attributes.  The
           second digit selects permissions for the user who owns the  file:  read
           (4),  write  (2),  and  execute  (1); the third selects permissions for
           other users in the file's group, with the same values; and  the  fourth
           for other users not in the file's group, with the same values.
           chmod never changes the permissions of symbolic links; the chmod system
           call cannot change their permissions.  This is not a problem since  the
           permissions  of  symbolic links are never used.  However, for each sym-
           bolic link listed on the command line, chmod changes the permissions of
           symbolic modes like u+s and g-s, and you can set (but  not  clear)  the
           bits with a numeric mode.


           The  restricted  deletion  flag  or  sticky  bit is a single bit, whose
           interpretation depends on the file type.  For directories, it  prevents
           unprivileged  users  from  removing or renaming a file in the directory
           unless they  own  the  file  or  the  directory;  this  is  called  the
           restricted  deletion  flag  for the directory, and is commonly found on
           world-writable directories like /tmp.  For regular files on some  older
           systems,  the  bit saves the program's text image on the swap device so
           it will load more quickly when run; this is called the sticky bit.


           Change the mode of each FILE to MODE.
           -c, --changes
                  like verbose but report only when a change is made
                  do not treat '/' specially (the default)
                  fail to operate recursively on '/'
           -f, --silent, --quiet
                  suppress most error messages
           -v, --verbose
                  output a diagnostic for every file processed
                  use RFILE's mode instead of MODE values
           -R, --recursive
                  change files and directories recursively
           --help display this help and exit
                  output version information and exit
           Each MODE is of the form '[ugoa]*([-+=]([rwxXst]*|[ugo]))+'.


           Written by David MacKenzie and Jim Meyering.


           Report chmod bugs to
           GNU coreutils home page: <>
           General help using GNU software: <>
           Report chmod translation bugs to <>
                  info coreutils 'chmod invocation'
           should give you access to the complete manual.

    GNU coreutils 8.4 June 2018 CHMOD(1)


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