- There are three types of permissions in files and folders in unix
- Read (r)
- Write (w)
- Execute (x)
- And, there is a classification of users called UGO (explained bellow):
- U ~> User (usually, you)
- G ~> Group (eg sudo group)
- O ~> Others
When you run $ ls -l
your output will be something like this:
-rwxrwxrwx@ 1 user staff 708301983 Aug 11 13:51 all.zip
-rw-r--r-- 1 user staff 0 Aug 22 22:10 chmodCheatSheet.md
-r--------@ 1 user admin 1692 Jul 6 10:13 deploykey.pem
drwxr-xr-x 3 user staff 102 Aug 20 19:14 deploynode
Where is a letter put a 1
and where is a -
put a 0
. Examples:
U | G | O |
---|---|---|
r w x | r w x | r w x |
1 1 1 | 1 1 1 | 1 1 1 |
So, user, group and others can read, write and excute the file or folder
U | G | O |
---|---|---|
r w - | r -- | r - x |
1 1 0 | 1 0 0 | 1 0 1 |
So, user can read and write, group can only read, finally other can read and execute
U | G | O |
---|---|---|
r - x | r w - | - - - |
1 0 1 | 1 1 0 | 0 0 0 |
U | G | O |
- w x | r - x | - - x |
0 1 1 | 1 0 1 | 0 0 1 |
Bin | Decimal | Representation |
---|---|---|
000 | 0 | - - - |
001 | 1 | - - x |
010 | 2 | - w - |
011 | 3 | - w x |
100 | 4 | r - - |
101 | 5 | r - x |
110 | 6 | r w - |
111 | 7 | r w x |
The syntax is something like this: $ chmod u/permissions g/permissions o/permissions file[or /dir/]
- So, if I run
$ chmod 777 file
<=>rwx rwx rwx
everybody can do anything with file - Or I run
$ chmod 744 dir
<=>rwx r-- r--
only user can read, write and execute, group and others only read dir. - Or run
$ chmod 200 file2
<=>-w- --- ---
only you can write file2
Thanks for reading, I hope it works! Follow me on Twita and GitHub
Refs:
- http://www.pa.msu.edu/~abdo/unixcc.html
- http://www.yourownlinux.com/2013/09/chmod-basics-of-filesdirectories.html
- Gabe Kutuzov (GitHub)
Thank you