scripting - Running a Bash script over ssh

Question

I'm trying to write a Bash script that will SSH into a machine and create a directory. The long-term goal is a bit more complicated, but for now I'm starting simple. However, as simple as it is, I can't quite seem to get it. Here's my code:

#!/bin/bash
ssh -T [email protected] <<EOI

# Fix "TERM environment variable undefined" error.
TERM=dumb
export TERM

# Store todays date.
NOW=$(date +"%F")
echo $NOW

# Store backup path.
BACKUP="/backup/$NOW"
[ ! -d $BACKUP ] && mkdir -p ${BACKUP}
echo $BACKUP

exit
EOI

It runs without any explicit errors. However, the echoed $NOW and $BACKUP variables appear empty, and the /backup directory is not created. How do I fix this?

Answer 1

The shell on the local host is doing variable substitution on $NOW and $BACKUP because the "EOI" isn't escaped. Replace

 ssh [email protected] <<EOI

with

 ssh [email protected] <<EOI