Running a part of shell script as a different user

Question

This question has been asked before, but I can't seem to get it work.

One of the solutions I tried is using here-document. I used the following code:

#!/bin/bash
su - mv2 <<EOSU
    DELIVER_BRANCH="development"
    echo ${DELIVER_BRANCH}
    exit;
EOSU

I tried the above code, bit echo ${DELIVER_BRANCH} doesn't print anything.

Answer 1

You want:

#!/bin/bash
su - mv2 <<'EOSU'
    DELIVER_BRANCH="development"
    echo "$DELIVER_BRANCH"
    exit;
EOSU

Note the single quotes around the first EOSU. If you omit them, the heredoc undergoes $-interpolation before being passed, which means that "$DELIVER_BRANCH" gets replaced with the current (to the shell invoking su) content of $DELIVERY_BRANCH, which is empty:

DELIVERY_BRANCH=production
cat <<'EOSU'
    DELIVER_BRANCH="development"
    echo "$DELIVER_BRANCH"
    exit;
EOSU

prints

DELIVER_BRANCH="development"
echo "$DELIVER_BRANCH"
exit;

whereas

DELIVERY_BRANCH=production
cat <<EOSU
    DELIVER_BRANCH="development"
    echo "$DELIVER_BRANCH"
    exit;
EOSU

prints

DELIVER_BRANCH="development"
echo production
exit;