lsps

#!/bin/sh
help() { cat <</help
Find entire ownership hierarchy of given process(es) from top to bottom
Usage: lsps [PID|COMMAND...]

Part of misc-scripts: https://github.com/adamhotep/misc-scripts
lsps 0.2.20240811.0, Copyright 2010+ by Adam Katz, GPL v2+
/help
}

# True when we have the given command(s).  No output.
we_have() { command -v "$@" >/dev/null 2>&1; }

# dummy pass-through to be overridden if colors are enabled
output() { cat; }
unset C04 C0

# looks like dash short circuits || but not && but its [ ... -a ... ] works fine
if [ -n "$CLICOLOR_FORCE" ] || [ -t 1 -a \
     "${TERM%256}$GREP_COLOR$LS_COLORS$CLICOLOR" != "${TERM%color}" ]
then
  if we_have grcat; then # use GRC for colors, https://github.com/adamhotep/grc
    output() { grcat conf.ps; }
  else
    C04=''  # underlined text
    C0=''     # color reset
  fi
fi

#PS_OPTIONS=user,ruser,pid,ppid,%cpu,%mem,vsz,rss,tt,stat,start,time,args
PS_OPTIONS=user,ruser,pid,ppid,%cpu,%mem,stat,start,time,args

lsps() {
  # find the parent process ID (assigned to $PPID) and print the process list
  PPID="$(ps -o "$PS_OPTIONS" "$1" \
    |awk -v TITLE=$TITLE -v C04="$C04" -v C0="$C0" '
      NR == TITLE {
        if (C04) $0 = C04 $0 C0
      }
      NR > !TITLE { print > "/dev/stderr" }
      NR > 1 { print $4 }
    ')" 2>&1	# sneaky: this "leaks" the process list to stdout via stderr
  TITLE=0	# we only want the title to display once per hierarchy
  if [ "$PPID" != 0 ] && [ "$PPID" != "$1" ]; then
    lsps "$PPID"  # RECURSIVE function call to find more ancestors
  fi
}

for PID in "$@"; do

  if [ "${PID#-h}" != "${PID#--help}" ]; then
    help
    exit
  fi

  TITLE=1	# show title for each PID (set to zero later in recursive calls)
  if [ "$PID" != "$1" ]; then echo; fi # add a space between PID lists

  if [ "$PID" -gt 0 ] 2>/dev/null; then
    lsps "$PID"
  elif we_have pgrep; then
    NEWPID=$(pgrep -- "$PID") # intentionally missing outer quotes
    if [ -n "$NEWPID" ]; then
      $0 $NEWPID  # intentionally missing quotes; we want 123 456, not "123 456"
    else
      echo "No PID(s) found matching '$PID'" >&2
      exit 2
    fi
  else
    echo "Invalid PID '$PID' and you do not have pgrep installed to find it" >&2
    exit 2
  fi
done |output