chmod

Convert between numeric and symbolic Unix file permission modes with a visual breakdown table.

Input

Enter a permission mode in either format:

FormatExampleDescription
Numeric (octal)755Three octal digits (0–7), one per entity
Symbolicrwxr-xr-xNine characters: read/write/execute for owner, group, other

The tool auto-detects which format you entered and converts to the other.

Permission Breakdown

Each digit in the numeric format encodes three bits:

BitValuePermission
Read4File/directory can be read
Write2File/directory can be written
Execute1File can be run / directory can be entered

The three digits represent Owner, Group, and Other (world) permissions respectively.

Example: `755`

  • Owner: 7 = 4+2+1 = rwx (read, write, execute)
  • Group: 5 = 4+0+1 = r-x (read, execute)
  • Other: 5 = 4+0+1 = r-x (read, execute)

Presets

Quick-access buttons for common permission modes:

ModeSymbolicTypical use
644rw-r--r--Regular files (owner reads/writes, others read)
664rw-rw-r--Shared files (owner and group read/write)
755rwxr-xr-xExecutables and directories
700rwx------Private files/directories (owner only)
777rwxrwxrwxFully open (use with caution)

The current mode is encoded in the URL as ?mode=<value>. Copy the URL to share or bookmark a specific permission.

Reset

Clears the input and removes the URL parameter.

See also

  • Unix Signals — signal numbers, names, and default actions for POSIX signals
  • Exit Codes — standard Unix/Linux process exit codes and their meanings