====== Saving STDERR to a variable ======

Getting the (standard) output of a command into a variable (and leaving any errors to go to the display) is simple:<code>var=`command`</code>or, as some people prefer:<code>var=$(command)</code>

In either case **echo $var** will then show you what was sent to STDERR.

However sometimes you want to get the "error" messages into the variable and leave the normal output displayed on the screen.  I say "error" in quotation marks because utilities like **time** show their own output on standard error STDERR whilst leaving the output of the command being timed going to standard output STDOUT.

In this case the method is what I would call "simple, but obscure":<code>{ stderr=$(command 2>&1 >&3 3>&-); } 3>&1</code>

So, for the specific use case of timing a command and then being able to use the duration afterwards:<code>{ t=$(/usr/bin/time -f %E command 2>&1 >&3 3>&-); } 3>&1
echo "Time taken = $t"</code>

If you actually want to redirect the standard output to a file at the same time, simply change the **3>&1** at the end to **3>/filename**

Thanks to https://unix.stackexchange.com/questions/474177 for this bit of bash expertise.

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