Bash c stdin was available to all commands vs. just the first one

[robertyates]

when data is piped into a bash script only the first command in the group should consume the data piped into the script

what was happening is that if a pipe was empty then it would fallback to the group stdin and this violates the expected behaviour for bash

e.g.

echo "test" | bash -c \'RESULT=$(cat | grep "nomatch" | head -1); echo "RESULT=[$RESULT]"\'

head should have received an empty input but instead it got "test" piped into the group, with this fix only the first command gets the bash -c piped input

the PR includes a failing test case and a fix that allows the test case to pass

[vercel]

@robertlyates is attempting to deploy a commit to the Vercel Labs Team on Vercel.

A member of the Team first needs to authorize it.

[robertyates]

@cramforce hopefully an easy merge, in more testing I discovered a bug / spec violation in my original PR - #102

the test case in here demonstrates the failure and then there's an easy fix, again, somewhat urgent on my side, appreciate all you're doing here