Assign variable in a pipleline

Question

I am trying to store stdin into a variable in a pipeline:

$ echo 'message' | variable="-" ; echo $variable

I know I can do a script for this; but I am just trying this way to understand.

Any idea why this isn't working?

Answer 1

You can do this:

echo 'message' | ( var="$(< /dev/stdin)"; echo "$var" )

Or:

echo 'message' | { var="$(< /dev/stdin)"; echo $var; }

Note: ( ... ) opens another new subshell after pipe.

---

Another way (using lastpipe bash>=4.2):

set +m;shopt -s lastpipe  # set +m disables job control
echo "hello world" | read test; echo test=$test
echo "hello world" | test="$(</dev/stdin)"; echo test=$test

Bash Manual says:

lastpipe

If set, and job control is not active, the shell runs the last command of a pipeline not executed in the background in the current shell environment.

Note that, job control is turned off by default in non-interactive shell.