Get permissions state of file or folder

ls –l myfile_name

The 3 values are shown in this order: Owner, group and others

Altering permissions

Set all permissions

sudo chmod 644 myfile_name

Add an individual permission

sudo chmod +rw myfile_name
sudo chmod g+rw myfile_name
sudo chmod o+rw myfile_name

(Example adds read and write permission for owner, group or others)

Remove an individual permission

sudo chmod -w myfile_name
sudo chmod g-w myfile_name
sudo chmod o-w myfile_name

(Example removes write permission for owner, group or others)