Increase sudo timeout from within a bash script

Question

I have a bash script that installs a lot of software. The whole process takes around 1h therefore I would like to increase the sudo timeout variable. I see it is possible as described here: Increase duration of Sudo.

However, I cannot find a description for the command line anywhere...
In my case I would like to make this change from within the script. I could put something like: sudo echo 'Defaults timestamp_timeout=300' >> /etc/sudoers at the first line within the bash script. This, however, is not allowed.

It's usually simpler to remove any sudos from inside the script, and run the whole script with sudo — steeldriver, Apr 25 '20 at 11:30
BTW here's why your attempt to modify the sudoers file failed: How to solve “permission denied” when using sudo with redirection in Bash? (I don't recommend doing that though) — steeldriver, Apr 25 '20 at 11:35
@steeldriver : I cannot run the whole script as sudo, it contains commands which specifically cannot be run with root privileges — maciek, Apr 25 '20 at 11:39
So how about dropping privileges for those specific commands (using sudo -u for example)? — steeldriver, Apr 25 '20 at 11:48
This would require the users to be known to the bash from inside the script? This is not the case... — maciek, Apr 25 '20 at 11:54
@steeldriver: I just tested that, it works, it correctly returns my name from inside the script. But now I have a problem that when the script calls sudo -u $SUDO_USER cp DIR/file file (being inside $HOME) . I get cp failed to access 'file': Permission denied. Is it possible to operate on $HOME as non-root while the script was called with sudo? — maciek, Apr 26 '20 at 20:02
OK, I have solved it, it was because $HOME points to a different place whether calling the script with/without sudo. Thank you for all the help! — maciek, Apr 27 '20 at 10:48

score 0 · Answer 1 · answered Apr 27 '20 at 13:51

I will post an answer to my problem in case anyone else runs into such issue in the future.
Thanks for the help @steeldriver.

Indeed, it is better to use sudo on the whole script and then escape commands within which specifically need to be run as the user with a prefix: sudo -u $SUDO_USER. Importantly, when the script is run with root privileges the $HOME changes, so be careful. In order to refer to the original user's home create a variable:

USER_HOME=$(sudo -u $SUDO_USER -H -s eval 'echo $HOME')

and then operate on paths with the prefix of $USER_HOME, if required.

Increase sudo timeout from within a bash script

1 Answers1