The Permission Model

Owner, group, other

Every file has three permission sets: for the owner, the group, and everyone else. Each set can allow read, write, and execute.

Like a shared office key

Think of a locked room: you (owner) have a key, your team (group) shares another, and visitors (other) may or may not get one. Each key can open the door, let you rearrange furniture (write), or just let you look inside (read).

Reading ls -l

The 10-character string shows type + three rwx triplets: owner, group, other.

ls -l deploy.sh

Output:

-rwxr-xr--  1 alice devs  842 Sep  4 09:00 deploy.sh
# owner: rwx | group: r-x | other: r--