chmod

chmod #

Change file mode.

Format is:

$ chmod <notation> <file>

Can only be done by the owner or the superuser.

This can be implemented using octal notation or symbolic notation. I favor symbolic notation.

Notation Meaning
u User
g Group owner
o Others
a All (default when not specificed)

These are modified using the folowing operators:

  • + - add permission
  • - - remove permission
  • = - all others are to be removed

Some common examples:

Notation Meaning
u+x Add execution permission for owner
u-x Remove execution permission for owner
+x Add execution permission for everyone
o-rw Others remove read and write permissions