What is Symbolic Notation?

While octal notation uses numbers (like 755), symbolic notation uses characters to represent permission targets, assignment operators, and access types (like u+x or go-w).

Symbolic mode is ideal when you want to modify a specific permission bit without changing the remaining bits on a file.

The 3 Components of a Symbolic Command

A symbolic permission statement consists of three parts: [WHO] [OPERATOR] [PERMISSION]

1. Who (Target Class)

u — User (File Owner)
g — Group
o — Others
a — All (User, Group & Others)

2. Operator

+ — Add specified permissions
- — Remove specified permissions
= — Set exact permissions (overwrite)

3. Permission Flag

r — Read
w — Write
x — Execute
s / t — Special bits

Symbolic Mode Examples

# Grant execute permission to the file owner onlychmod u+x script.sh# Revoke write permissions from group and publicchmod go-w document.pdf# Set exact permissions for all users (read and execute)chmod a=rx public_script.sh# Combine multiple symbolic modificationschmod u=rwx,g=rx,o=r application.bin

Reading Symbolic String Format

When running ls -l, permissions are displayed as a 10-character string:

- r w x r - x r - x

Position 1: File type (- file, d directory, l symlink).
Positions 2–4: Owner permissions (rwx).
Positions 5–7: Group permissions (r-x).
Positions 8–10: Others permissions (r-x).

Symbolic Permission Notation Guide