chmod Calculator

Visualize Unix/Linux file permissions with special bits support

Setuid(4xxx — execute as file owner)

Setgid(2xxx — execute as group owner)

Sticky Bit(1xxx — only owner can delete, used for /tmp)

chmod command

chmod 644 <file>

Symbolic

rw-r--r--

Octal input

3-digit: 644

4-digit: 0644

rw-r--r--Regular file (owner writes, others read)

rwxr-xr-xExecutable / directory (owner full, others execute)

rw-------Private file (owner read/write only)

rwxrwxrwxWorld-writable (not recommended in production)

r--------Read-only (commonly used for key files)

rwsr-xr-xsetuid executable (e.g. /usr/bin/sudo)

rwxrwxrwtSticky directory (e.g. /tmp — anyone can write, nobody can delete others' files)