What does chmod 755 mean?

chmod 755 means the owner has full permissions (read, write, execute = 7), while group and others have read and execute only (5). It's commonly used for scripts and executables that should be readable by all but only editable by the owner.

What is the difference between numeric and symbolic notation?

Numeric notation uses numbers (0-7) for each permission set, like 755. Symbolic notation uses letters: r (read), w (write), x (execute), like rwxr-xr-x. Both represent the same permissions in different formats.

What chmod should I use for web files?

For web files: directories typically need 755, PHP/scripts need 755 or 644, regular files need 644. Never use 777 in production as it creates security vulnerabilities.

chmod Calculator

Calculate Unix/Linux file permissions easily

Permission

Owner

Group

Others

Read (4)

Write (2)

Execute (1)

Octal (Numeric):

Symbolic:

rwxr-xr-x

chmod Command:

chmod 755 filename

chmod Calculator

Common Permissions