How do I run a 'sudo' command inside a script?

Solution 1:

It is rarely a good idea to have sudo inside scripts. Instead, remove the sudo from the script and run the script itself with sudo:

sudo myscript.sh

That way, all commands within the script will be run with root privileges and you only need to give the password once when launching the script. If you need a particular command within the script to be run without sudo privileges, you can run it as a regular user with (thanks Lie Ryan):

sudo -u username command 

The space is irrelevant, it should not affect anything, there is always a space between a command and its arguments.

Solution 2:

You could possibly modify the sudoers file.

Run sudo visudo.

Add an entry for your username and the script that you would like to run without being asked for a password.

username ALL=(ALL) NOPASSWD: /path/to/script

Solution 3:

You could try something like:

echo "PASSWORD" | sudo -S ./playback_delete_data_patch.sh 09_delete_old_data_p.sql

This is not the most secure thing to do since you are writing a sudoer password in plain text. To make it a little more secure you can create a variable and read the sudo password into the variable and then you could execute the command as:

echo $PASSWORD | sudo -S ./playback_delete_data_patch.sh 09_delete_old_data_p.sql

Also, if you do not mind all your commands being executed as root you can simple execute your script using sudo, as previously suggested.

sudo ./myscript

Solution 4:

This answer is similar to terdon's answer. I would also suggest running the main script with sudo so the script can run without having to ask for the user's password during its execution.

However, in case you want to drop root privileges to some of the commands and run them as the actual user who invoked the command with sudo, you can check for the $SUDO_USER variable to figure out the original user.

This is an example script of how you could achieve that:

#!/bin/bash

# ref: https://askubuntu.com/a/30157/8698
if ! [ $(id -u) = 0 ]; then
   echo "The script need to be run as root." >&2
   exit 1
fi

if [ $SUDO_USER ]; then
    real_user=$SUDO_USER
else
    real_user=$(whoami)
fi

# Commands that you don't want running as root would be invoked
# with: sudo -u $real_user
# So they will be run as the user who invoked the sudo command
# Keep in mind if the user is using a root shell (they're logged in as root),
# then $real_user is actually root
# sudo -u $real_user non-root-command

# Commands that need to be ran with root would be invoked without sudo
# root-command