ptree for linux

ptree.sh

#!/bin/bash

if [[ $# -gt 0 ]]; then
  if expr $1 : '^[0-9]*$' > /dev/null; then
    ARGS="-p $1"
    shift
    while [[ $# -gt 0 ]]; do
      ARGS="${ARGS},$1"
      shift
    done
  else
    ARGS="-u $1"
  fi
else
  ARGS="-e"
fi

ps -H -o pid,cmd $ARGS | sed -n -e 's/^ *\([0-9]*\) \( *\)\(.*\)/\2\1 \3/' -e '2,$p'