sudo

andy.l · 12-05-2017, 02:48 AM

Hi,
trying to understand what the real differences between

Code:

sudo su - UserName

and

Code:

sudo -u UserName -i

.

Wouldn't those 2 commands provide the same result?

/Andy

business_kid · 12-05-2017, 04:37 AM

Use sudo OR su, not both; sudo gives 1 command, su changes indefinitely.

frankbell · 12-05-2017, 08:50 PM

If you run sudo su, sudo will run one instance of su, but that instance will be persistent until you type exit to leave su. Sudo fetishists consider this a transgression against sudo. Others see it as a useful workaround.

As for the -i switch, this is from man sudo.

Quote:

-i, --login
Run the shell specified by the target user's password data‐ base entry as a login shell. This means that login-specific resource files such as .profile or .login will be read by the shell. If a command is specified, it is passed to the shel for execution via the shell's -c option. If no command is
specified, an interactive shell is executed. sudo attempts to change to that user's home directory before running the shell. The command is run with an environment similar to thene a user would receive at log in. The Command Environment section in the sudoers(5) manual documents how the -i option affects the environment in which a command is run when the sudoers policy is in use.

In most cases, when all users are using the default shell, whatever that might be, it is irrelevant. If multiple shells are installed, it may be a useful switch.

!!! · 12-06-2017, 01:33 AM

Just fyi: a TL;dr looooong story about sudo/su which I often see posted:
https://www.linuxquestions.org/quest...ml#post5673461

pan64 · 12-06-2017, 06:46 AM

apparently they produce the same result (probably), but not the same way.
as it was already mentioned sudo and su must not be used together, that is not the intended way. differences/side effects were already explained, but in short:
sudo su will hide the original user, will fork an additional process
sudo su and sudo <user> may require different permission settings.