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Unix Permissions / chmod Calculator
Permissions
owner:
group:
others:

Results :
Numeric (Octal) Notation 777
Symbolic Notation rwxrwxrwx

Examples:
chmod 777 <file_name>
chmod a=rwx <file_name>


There are three specific UNIX/Linux file system permissions - read (r), write (w), and execute (x). Permissions are grouped into three sets or triads, each defining access for different scope or class: user/owner (u), group (g), and everyone else/others (o). Permissions can be presented either in numeric (octal) or symbolic notations. For example: 764 or rwxrw-r--, respectively. The leftmost set/triad, in this case 7 or (rwx), defines user/owner (u) permissions, the second from the left - 6 or (rw-) - group (g) permissions, and the rightmost - 4 or (r--) - permissions for others (o).

Numeric values for permissions and corresponding symbolic representations are shown in the table below:

Numeric Symbolic Permission
0 --- none
1 --x execute only
2 -w- write only
3 -wx write and execute
4 r-- read only
5 r-x read and execute
6 rw- read and write
7 rwx read, write, and execute

Special modes or special permissions - setuid, setgid, and sticky mode, if defined, are represented by the forth (leading) octal character in the numeric notation. In the symbolic notation the setuid bit is set in the triad for the user, the setgid bit is set in the triad for the group and the sticky bit is set in the triad for others.

Numeric values for special permissions and corresponding symbolic representations are shown in the table below:

Special mode Numeric Symbolic
setuid 4 third character in the user triad: s (also executable)
S (not executable)
setgid 2 third character in the group triad: s (also executable)
S (not executable)
sticky bit 1 third character in the others triad: t (also executable)
T (not executable)

Note: Special permissions are not covered by this calculator.