chmod

Change file mode bits (permissions).

$ chmod

File(s)

Mode type

Symbolic (u+x)

Octal (755)

Scope

Owner (u)

Group (g)

Others (o)

All (a)

Operator

Add (+)

Remove (-)

Set (=)

Permissions

Read (r)

Write (w)

Execute (x)

Execute if dir (X)

Set UID/GID (s)

Sticky (t)

Examples

# Add execute permission
chmod +x script.sh

# Set exact permissions (octal)
chmod 755 script.sh

# Recursive directory
chmod -R 644 /path/to/files

# Symbolic: add write for group
chmod g+w file.txt

# Reference file
chmod --reference=ref.txt target.txt