Command Line: chmod
For Linux
Symbols
Get file permissions: ls-l
- R – read
- W – write
- X – execute
User Levels
- Owner
- Group
- World
Permissions
- Assign file permissions:
chmod permissions filename
- Assign user/group permissions:
chmod user group world filename
Permission numbers
- 4 read (r)
- 2 write (w)
- 1 execute (x)
Practical Examples
- chmod 400 mydoc.txt read by owner
- chmod 040 mydoc.txt read by group
- chmod 004 mydoc.txt read by anybody (other)
- chmod 200 mydoc.txt write by owner
- chmod 020 mydoc.txt write by group
- chmod 002 mydoc.txt write by anybody
- chmod 100 mydoc.txt execute by owner
- chmod 010 mydoc.txt execute by group
- chmod 001 mydoc.txt execute by anybody
Combinations
- 7 = 4+2+1 (read/write/execute)
- 6 = 4+2 (read/write)
- 5 = 4+1 (read/execute)
- 4 = 4 (read)
- 3 = 2+1 (write/execute)
- 2 = 2 (write)
- 1 = 1 (execute)
Common Examples
- chmod 666 mydoc.txt read/write by anybody
- chmod 755 mydoc.txt rwx for owner, rx for group and rx for the world
- chmod 777 mydoc.txt read, write, execute for all
Summarized from Linux.org