Bash: prefix output of all commands with timestamp

force-prefix-init-script.bash

function process_command() {
  if [ "$$" -eq "$BASHPID" ]; then
    if [[ "$HANDLER_INSTALLED" -ne "1" ]]; then
      exec > >(
        trap "" INT TERM;
        awk '{ print strftime("%Y-%m-%d %H:%M:%S ", systime()) $0; fflush(stdout) }'
      )
      exec 2> >(
        trap "" INT TERM;
        awk '{ print strftime("%Y-%m-%d %H:%M:%S ", systime()) $0; fflush(stdout) }' >&2
      )
      export HANDLER_INSTALLED=1
    fi
  fi
}

function prompt_command() {
  exec &>/dev/tty
  export HANDLER_INSTALLED=0
  sleep 0.3
}

PROMPT_COMMAND="prompt_command"
trap process_command DEBUG

Quick and dirty, was just wondering if this can be done. The sleep is unfortunate, but the bash prompt will otherwise occasionally appear in the middle of the command outputs. There ought to be a better way to do that, suggestions welcome.

This could be used e.g. in an ENTRYPOINT in a Docker container that runs some CI/CD jobs, but the environment does not otherwise tell you which parts of which jobs are slow...