CODEWITHSUNDEEP
linuxbashpermissionssudo
Steve Bennett
Steve Bennett

Reputation: 126445

Should bash scripts use sudo, or assume sudo?

Which pattern is preferable:

#!/bin/bash
echo Installing blah
apt-get install -y blah

...which will fail if run without root perms, or:

#!/bin/bash
echo Installing blah
sudo apt-get install -y blah

...which will succeed as long as the user has sudo access.

I have tended to use the second pattern, but it seems to be rare, so I'm asking what its disadvantages are. The benefits I see are:

I guess downsides include that the use of root permissions might be surprising ("I didn't type sudo, so I didn't expect anything like apt-get to be run...."). What else?

Upvotes: 6

Views: 1733

Answers (3)

chepner
chepner

Reputation: 531758

The second option is the correct option. Commands that don't require root access should not be run as root just to simplify your script. Commands that do require root access (or access by any specific user, for that matter) should be run by sudo. For clarity, you can use the -p option to sudo to present a custom prompt which can explain exactly why the user is asked for their password.

Option two is also preferable because sudo is highly configurable, and the user may already have permission to run specific commands with sudo without a password, so it's possible the user would not be inconvenienced by a password prompt. It's less likely that the user is allowed to sudo arbitrary commands (such as your script) without a password.

Upvotes: 2

Elliott Frisch
Elliott Frisch

Reputation: 201467

You could always test if the user is root (id -u gets the uid of the current user, and 0 is root), and run sudo if they aren't -

#!/bin/bash

echo Installing blah
CMD=""
if [ "$(id -u)" != "0" ]; then
  CMD="sudo"
fi
${CMD} apt-get install -y blah

The more common approach would be to exit with an error condition if they aren't root,

#!/bin/bash
if [ "$(id -u)" != "0" ]; then
  echo "sudo $0 (must run as root)"
  exit 1
fi
echo Installing blah
apt-get install -y blah

Upvotes: 2

slashRahul
slashRahul

Reputation: 555

I will prefer second Pattern, because running few commands with sudo is better rather then running entire script with root permissions in which some commands are needless to have root access and so if you perform these commands with root user further using that command outputs will again need root access or you will have to change the ownership. So I will prefer second approach where sudo is necessary do it, else go local user.

Upvotes: 2

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