How to execute a group of commands as another user in Bash?

bash su
Nathan Osman picture Nathan Osman · Jul 20, 2013 · Viewed 97k times · Source

There are already some existing questions asked here about running commands as another user. However, the question and answers focus on a single command instead of a long group of commands.

For example, consider the following script:

#!/bin/bash
set -e

root_command -p param1  # run as root

# these commands must be run as another user
command1 -p 'parameter with "quotes" inline'
command2 -p 'parameter with "quotes" inline'
command3 -p 'parameter with "quotes" inline'

There are a couple of important points to note here:

  • The final three commands must be run as another user using su or sudo. In the example there were three commands, but suppose that there were many more...

  • The commands themselves make use of single and double quotes.

The second point above prevents the use of the following syntax:

su somebody -c "command"

...since the commands themselves contain quotes.

What is the proper way to "group" the commands and run them under another user account?

Answer

Barmar picture Barmar · Jul 20, 2013

Try this:

su somebody <<'EOF'
command1 -p 'parameter with "quotes" inline'
command2 -p 'parameter with "quotes" inline'
command3 -p 'parameter with "quotes" inline'
EOF

<< introduces a here-doc. The next token is the delimiter, and everything up to a line beginning with the delimiter is fed as standard input to the command. Putting the delimiter in single quotes prevents variable substitution within the here-doc.

Related questions

How to run script as another user without password?

I have script.sh that must be run as user2. However, this script can only be run under user1 in my application. I would like the following command to run: su user2 -C script.sh but be able to run …

Read More
How do I use su to execute the rest of the bash script as that user?

I've written a script that takes, as an argument, a string that is a concatenation of a username and a project. The script is supposed to switch (su) to the username, cd to a specific directory based upon the project …

Read More
How do you find the original user through multiple sudo and su commands?

When running a script via sudo or su I want to get the original user. This should happen regardless of multiple sudo or su runs inside of each other and specifically sudo su -.

Read More