chmod command help

 chmod - change file access permissions
 

SYNOPSIS

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

DESCRIPTION

 This manual page documents the GNU version of chmod.
 chmod changes the permissions 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 permissions.
 
 The format of a symbolic mode is `[ugoa...][[+-=][rwxXsュ
 tugo...]...][,...]'. Multiple symbolic operations can be
 given, separated 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 permissions selected to be
 added to the existing permissions of each file; `-' causes
 them to be removed; and `=' causes them to be the only
 permissions that the file has.
 
 The letters `rwxXstugo' select the new permissions for the
 affected users: read (r), write (w), execute (or access
 for directories) (x), execute only if the file is a direcュ
 tory or already has execute permission for some user (X),
 set user or group ID on execution (s), save program text
 on swap device (t), the permissions that the user who owns
 the file currently has for it (u), the permissions that
 other users in the file's group have for it (g), and the
 permissions that other users not in the file's group have
 for it (o).
 
 A numeric mode is from one to four octal digits (0-7),
 derived by adding up the bits with values 4, 2, and 1.
 Any omitted digits are assumed to be leading zeros. The
 first digit selects the set user ID (4) and set group ID
 (2) and save text image (1) attributes. The second digit
 selects permissions for the user who owns the file: read
 (4), write (2), and execute (1); the third selects permisュ
 sions 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.
 
 is not a problem since the permissions of symbolic links
 are never used. However, for each symbolic link listed on
 the command line, chmod changes the permissions of the
 pointed-to file. In contrast, chmod ignores symbolic
 links encountered during recursive directory traversals.
 

OPTIONS

 -c, --changes
 like verbose but report only when a change is made
 
 -f, --silent, --quiet
 suppress most error messages
 
 -v, --verbose
 output a diagnostic for every file processed
 
 --reference=RFILE
 use RFILE's mode instead of MODE values
 
 -R, --recursive
 change files and directories recursively
 
 --help display this help and exit
 
 --version
 output version information and exit
 
 Each MODE is one or more of the letters ugoa, one of the
 symbols +-= and one or more of the letters rwxXstugo.
 

REPORTING BUGS

 Report bugs to <bug-fileutils@gnu.org>.
 

SEE ALSO

 The full documentation for chmod is maintained as a Texュ
 info manual. If the info and chmod programs are properly
 installed at your site, the command
 
 info chmod
 
 should give you access to the complete manual.