Chmod
Unix permissions calculator
| Read | Write | Execute | Octal | |
|---|---|---|---|---|
| Owner | 6 | |||
| Group | 4 | |||
| Others | 4 |
Numeric Format
644
Symbolic Format
rw-r--r--
$ chmod 644 filename
$ chmod 644 -R directory/
Frequently Asked Questions
What is chmod?
chmod (change mode) is a Unix/Linux command that sets file permissions. It controls who can read, write, or execute files and directories.
What do the permission numbers mean?
Each digit represents permissions for owner, group, and others. Values: 4=read, 2=write, 1=execute. Example: 755 means owner has all permissions (7=4+2+1), group and others can read and execute (5=4+1).
What is the difference between symbolic and octal notation?
Octal uses numbers (755). Symbolic uses letters: u(user), g(group), o(others), a(all) with r(read), w(write), x(execute). Example: chmod u+x adds execute for owner.