Run bash script with sudo but create files with user as owner - bash

Question

I have a bash script, create-file.sh, that creates a file named a:
$ cat create-file.sh
# /bin/bash
touch a
When I run the script it creates a file 'a' with my user as owner.
$ ./create-file.sh
$ ls -l
-rw-r--r-- 1 shai wheel 0 Aug 16 17:19 a
However when I run the script under sudo the file is created with root as user:
$ sudo ./create-file.sh
$ ls -l
-rw-r--r-- 1 root wheel 0 Aug 16 17:19 a
Is there a way to tell a script that runs under sudo to create the file with my user as owner?
you would be correct to say that a script that touches a single file does not need to run under sudo. This example is of course a reduction of the original problem, my script has much more and does need to run under sudo, but I still want the files to be created with my user as owner.

Answer 1

sudo exports the original username as SUDO_USER; you can chown to that.
#!/bin/bash
touch a
[[ $SUDO_USER ]] && chown "$SUDO_USER" a
Similarly, if your sudo configuration allows (as is default) root to drop privileges to any other user without an explicit password prompt, you can take advantage of that:
#!/bin/bash
# drop privileges back to non-root user if we got here with sudo
depriv() {
if [[ $SUDO_USER ]]; then
sudo -u "$SUDO_USER" -- "$#"
else
"$#"
fi
}
depriv touch a