How to trick an application into thinking its stdout is a terminal, not a pipe

Question

I\'m trying to do the opposite of \"Detect if stdin is a terminal or pipe?\".

I\'m running an application that\'s changing its output format because it detects a pip

Answer 1

Updating @A-Ron's answer to a) work on both Linux & MacOs b) propagate status code indirectly (since MacOs script does not support it)

faketty () {
  # Create a temporary file for storing the status code
  tmp=$(mktemp)

  # Ensure it worked or fail with status 99
  [ "$tmp" ] || return 99

  # Produce a script that runs the command provided to faketty as
  # arguments and stores the status code in the temporary file
  cmd="$(printf '%q ' "$@")"'; echo $? > '$tmp

  # Run the script through /bin/sh with fake tty
  if [ "$(uname)" = "Darwin" ]; then
    # MacOS
    script -Fq /dev/null /bin/sh -c "$cmd"
  else
    script -qfc "/bin/sh -c $(printf "%q " "$cmd")" /dev/null
  fi

  # Ensure that the status code was written to the temporary file or
  # fail with status 99
  [ -s $tmp ] || return 99

  # Collect the status code from the temporary file
  err=$(cat $tmp)

  # Remove the temporary file
  rm -f $tmp

  # Return the status code
  return $err
}

Examples:

$ faketty false ; echo $?
1

$ faketty echo '$HOME' ; echo $?
$HOME
0

embedded_example () {
  faketty perl -e 'sleep(5); print "Hello  world\n"; exit(3);' > LOGFILE 2>&1