Output prefix with timestamp

output_prefix.sh

#!/usr/bin/env bash

{
  echo foo 1
  sleep 1
  echo bar 1 >&2
  echo foo 2
  sleep 1
  echo bar 2 >&2
} \
  2> >(sed "s/^/$(date '+%Y-%m-%d %H:%M:%S') [ERR] /" >&2) \
  > >(sed "s/^/$(date '+%Y-%m-%d %H:%M:%S') [INF] /")

output_prefix_function.sh

#!/usr/bin/env bash

output-prefix() {
  "$@" \
    2> >(sed "s/^/$(date '+%Y-%m-%d %H:%M:%S') [ERR]${prefix} /" >&2) \
    > >(sed "s/^/$(date '+%Y-%m-%d %H:%M:%S') [INF]${prefix} /")
}

output-prefix ./loop.sh foo