chmod calculator
Tick the permissions to get the chmod number and the rwx string, or type a number like 755 to decode it.
| Read | Write | Execute | |
|---|---|---|---|
| Owner | |||
| Group | |||
| Others |
Symbolic
Frequently asked questions
What do 755 and 644 mean?
Each digit is one group: owner, group, others. 4 = read, 2 = write, 1 = execute, added up. 755: the owner can do everything, others can read and run (folders, scripts). 644: the owner can read and write, others only read (normal files).
Why is 777 a bad idea?
It lets every user on the server change or replace the file. On a web server that is an easy way in for an attacker. Fix the owner instead of opening the permissions.
What are setuid, setgid and sticky?
The optional fourth (leading) digit: 4 setuid runs a program as its owner, 2 setgid as its group (or makes new files in a folder inherit the group), 1 sticky stops users from deleting others’ files in a shared folder like /tmp.