try/finally with bash shell

Question

I have these three lines:

  export bunion_uds_file="$bunion_socks/$(uuidgen).sock";
  "$cmd" "$@" | bunion
  rm -f "$bunion_uds_file"

I need to make sure the last line always executes..I could do this:

  export bunion_uds_file="$bunion_socks/$(uuidgen).sock";
  (
    set +e
    "$cmd" "$@" | bunion
    rm -f "$bunion_uds_file"
  )

or maybe like this:

  export bunion_uds_file="$bunion_socks/$(uuidgen).sock";
  "$cmd" "$@" | bunion && rm -f "$bunion_uds_file" || rm -f "$bunion_uds_file"

I assume creating the subshell and using set +e is slightly less performant etc.

Answer 1

You could set a trap:

#!/bin/bash

export bunion_uds_file="$bunion_socks/$(uuidgen).sock"
trap 'rm -f "$bunion_uds_file"' EXIT

"$cmd" "$@" | bunion

This would make the rm -f command run whenever the shell session terminates, except for when terminating by the KILL signal.

As mosvy points out in comments, if this is a socket that needs to be cleaned up before use, it would be easier to remove it before recreating and using it:

#!/bin/bash

export bunion_uds_file="$bunion_socks/$(uuidgen).sock"
rm -f "$bunion_uds_file" || exit 1

"$cmd" "$@" | bunion