chmod permission
Estimated reading time: 2 minuteswhat is chmod
chmod means change mode . chmod can change the file permission.
| short hand | Full |
|---|---|
| u | user |
| g | group |
| o | other |
chmod basic
# cli
ls -l
# output
drwxrw-r--
user = first 3 position without d = rwx group = next 3 position = rw- other = last 3 position = r–
- first position
distype
permission lists
| cli name | Full name | number value |
|---|---|---|
| r | read | 4 |
| w | write | 2 |
| x | excute | 1 |
| - | not permit | 0 |
user = rwx => 4+2+1 = 7
group = rw- => 4+2+0 = 6
others = r-- => 4+0+0 = 4
last result => chmod 764 => rwxrw-r--
binary system
- permission = 1
- no permit = 0
user = rwx => 111 => binary to decimal => 7
group = rw- => 110 => binary to decimal => 6
others = r-- => 100 => binary to decimal => 4
last result=> chmod 764 => rwxrw-r--
chmod pettern
chmod <options> <permissions> <filename>
- options
-Rrecursive, i.e. include objects in subdirectories-fforce, forge ahead with all objects even if errors occur-vverbose, show objects processed
how to use chmod
chmode u+rwx, g+rw-, o+r-- desired_file
# number system
chmod 764 desired_file