This post is designed to be updated as soon as new tricks come handy.
Useful commands
| Instruction | Command |
|---|---|
| Change user | su - <username> |
| Change owner | chown user:group -R folder |
| Check owner & permissions | stat filename |
| List all users with UID | cut -d: -f1,3 /etc/passwd |
| List all groups with GID | getent group |
Linux ownership system
rwx
Owner and permissions: typing la we get informations about the pemissions about a file or a folder
example
-rw-r--r-- 1 lorenzi lorenzi 4,3K 19 gen 11.22 .bashrc
drwxr-xr-x 26 lorenzi lorenzi 4,0K 8 feb 14.01 bench/
the first column is divided in three parts:
| Owner of the file (U) | User group of the owner (G) | all others (O) |
|---|---|---|
rw- |
r-- |
r-- |
the first character indicates the file type, that for example in the bench case is a directory.
Octal characters
A mapping can be done from the three permissions to a single octal value. This mapping is one-to-one.
r (read): 4 w (write): 2 x (execute): 1