I have put together the following to detect if a script is being run by Bash or not:

```
################################################################################
# Checks whether execution is going through Bash, aborting if it isn't. TinoSino

current_shell="$(
  ps                  `# Report a snapshot of the current processes` \
      -p $$           `# select by PID` \
      -o comm         `# output column: Executable namename` \
  |\
  paste               `# Merge lines of files ` \
      -s              `# paste one file at a time instead of in parallel` \
      -               `# into standard output` \
  |\
  awk                 `# Pick from list of tokens` \
      '{ print $NF }' `# print only last field of the command output`
)"

current_shell="${current_shell#-}" # Remove starting '-' character if present

if [ ! "${current_shell}" = 'bash' ]; then

  echo "This script is meant to be executed by the Bash shell but it isn't."
  echo 'Continuing from another shell may lead to unpredictable results.'
  echo 'Execution will be aborted... now.'

  return 0

fi

unset current_shell
################################################################################

```

I am not asking you specifically to code review it because you would be sending me to CodeReview; my question is:

* how would you go about *testing* whether this "execution guard" put at the top of my script does indeed do its job *reliably*?

I am thinking about installing Virtual Machines and on each machine to install things like `zsh`, `csh`, etc. But it looks way too time-consuming to me. Better ways to do this?

Should you spot an immediate mistake do point it out to me though please. Just glaring bugs waving their legs waiting to be squashed *should* be squashed, I think.