How to send stderr in email shell script (ash)

Question

I wrote a shell script that I use under ash, and I redirect stderr and stdout to a log file. I would like that log file to be emailed to me only if stderr is not empty.

I tried:

exec >mylog.log 2>&1

# Perform various find commands

if [TEST_IF_STDERR_NOT_EMPTY]; then
/usr/bin/mail -s "mylog" [email protected] < mylog.log
fi

My question is twofold:

1- I get a -sh: /usr/bin/mail: not found error. It seems that the mail command doesn't exist under ash (or at least under my linux box, which is a Synology NAS), what would be the alternative? Worst case, perl is available, but I would prefer to use standard sh commands.

2- How to I test that stderr is not empty?

Thanks

Answer 1

How to check if file is empty in bash

As for the first question, in your code you are calling mail but lower in the post you are calling email. Check your code and make sure it is mail.

Use which mail to get the full path. Maybe it is not installed in /usr/bin/. Use find to locate mail. If you can go to another shell, run it and then execute which mail to get the full path of mail in case the path is set up in the alternative shells.