chmod(1)                                                 chmod(1)



NAME
     chmod - changes the permissions of a file

SYNOPSIS
     chmod mode file...

ARGUMENTS
     file Specifies the files that will have its permissions
          changed.

     mode Specifies the mode to which the file will be changed.
          The modes are:

          4000 Sets user ID on execution.

          2000 Sets group ID on execution.

          1000 Sets the sticky bit, see chmod(2).

          0400 Allows read access by owner.

          0200 Allows write access by owner.

          0100 Allows execution (search in directory) by owner.

          0070 Allows read, write, and execution by group.

          0007 Allows read, write, and execution by others.

DESCRIPTION
     The permissions of the named files are changed according to
     mode, which may be absolute or symbolic.  An absolute mode
     is an octal number constructed from the R of the modes shown
     above.

     A symbolic mode has the form:

        [who] op permission [ op permission]

     The who part is a combination of the letters u (for user's
     permissions), g (group) and o (other).  The letter a stands
     for ugo, the default if who is omitted.

     The op option can be + to add permission to the file's mode,
     - to take away permission, or = to assign permission
     absolutely (all other bits will be reset).

     The permission option is any combination of the letters r
     (read), w (write), x (execute), s (set owner or group ID)
     and t (save text, or sticky); u, g, or o indicate that
     permission is to be taken from the current mode.  Omitting
     permission is only useful with = to take away all



January 1992                                                    1

chmod(1)                                                 chmod(1)



     permissions.

     Multiple symbolic modes separated by commas may be given.
     Operations are performed in the order specified.  The letter
     s is only useful with u or g and t only works with u.

     Only the owner of a file (or the superuser) may change its
     mode.  Only the superuser may set the sticky bit.  In order
     to set the group ID, the group of the file must correspond
     to your current group ID.

EXAMPLES
     The command:

        chmod 755 filename

     changes the mode of filename to: read, write, execute
     (400+200+100) by owner; read, execute (40+10) for group;
     read, execute (4+1) for others. An ls -l of filename shows
     [-rwxr-xr-x filename] that the requested mode is in effect.

     The command:

        chmod = filename

     will take away all permissions from filename, including
     yours.  The command:

        chmod o-w file

     denies write permission to others.  The command:

        chmod +x file

     makes a file executable.

FILES
     /bin/chmod
          Executable file

SEE ALSO
     ls(1), chown(1), csh(1), ksh(1), sh(1)

     chmod(2) in A/UX Programmer's Reference

     A/UX Essentials

     A/UX Local System Administration







2                                                    January 1992