“There are three ways to change your identity. Log back in as another user, the su command, or sudo. su lets you start a new shell session as that user or issue a single command as that one. sudo can define specific commands that a user can use. The choice depends mainly on the OS you’re using- as each one works a little differently. To start shell as another user, the syntax is su [-[l]] [user].-l will create a login shell for that user. -l can be seen as just -. So to change to superuser status you would type su -, then your password. Now you’ll see ‘root’ in place of the username. Always remember to use ‘exit’ to resume using the OS as a normal user. You can also type su -c ‘command’ to run just one single command as a superuser. Ex: su -c ‘ls -l /root/*’.
An admin can allow users to execute certain commands with sudo. For example, sudo ducky_script, then typing your password, will let you as a regular user run the ducky_script as a regular user. sudo -l will show you what privileges you have.
You can also use chown to change the owner or group owner of a file. It looks like this: chown [owner] [:[group]] file.. . If the argument looked like this: shannon:users it would change the ownership from its current one to shannon, and the group to users. :admins would change the group owner to admins, but the file owner is the same. So if I wanted to change the ownership from me to Darren, I would put sudo chown darren: ~darren/example.txt.
Now that you know some of the reasons why we have passwords for users, lets change those passwords. Use the syntax passwd [user]. To change it, type passwd. Type your current password, and the new one. passwd will make you use a strong password, so it’ll deny crappy ones. Check out the passwd man page for more options for this command.
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