psg: a wrapper to output ps to a pager, colorized and with a filter option

11-functions.bashrc

#!/usr/bin/env bash
# executed by bash(1) for non-login shells.

# ==============================
# FUNCTIONS
# ==============================

# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# a wrapper to output ps to a pager, colorized and with a filter option
psg() {
  Help() {
    cat <<- HEREDOC
	
	Display a colorized list of active processes from ps in Less
	with optional command line pattern filtering.
	
	Syntax:       psg [-h] ["<pattern>"]
	options:
	  -h          Print this Help.
	  "<pattern>" optional: This pattern will use &/ filter in Less
	
	HEREDOC
  }
  
  local OPTIND=0
  while getopts ":h" option; do
    case $option in
      h)  Help; return 0 ;;
      \?) echo -e "Unknown option: -$OPTARG \n"       >&2; Help; return 1;;
      : ) echo -e "Missing argument for -$OPTARG \n"  >&2; Help; return 1;;
      * ) echo -e "Unimplemented option: -$option \n" >&2; Help; return 1;;
    esac
  done
  shift $((OPTIND-1))
  
  if [[ -z $(command -v "bat") ]]; then
    echo "Requirements: bat could not be found:"
    echo "sudo apt install bat"
    return 0
  fi
  
  if [[ -z $1 ]]; then
    _LESS_PROMPT="Output of ps command"
    _LESS_CMDS="--"
  else
    _LESS_PROMPT="Output of ps command (clear filter with &+Enter)"
    _LESS_CMDS=$(echo -n -e "+&rss elapsed|${1}\n/${1}\np")
  fi
  
  # Less < 632: sticky --header option
  if [[ $(less -V | awk 'NR==1 {printf $2}') -gt 632 ]]; then
    _LESS_HEADER="--header 1"
  fi
  
  ps f -o user,pid,ppid,s,ni,nlwp,tty,%cpu,rss,etimes,args -p $(ps -o pid= -N --ppid $$ --pid $$) \
    | awk 'NR==1 {o=$0; a=match($0,$11);}; \
      BEGIN{now=systime()} NR>1 {o=$0; $9=int(10*$9/1024)/10"M"; $10=strftime("%m/%d-%H:%M:%S", now-$10);} \
      { printf "%-8s %7s %7s %1s %4s %4s %6s %5s %8s %-14s %s\n", $1, $2, $3, $4, $5, $6, $7, $8, $9, $10, substr(o, a);}' \
    | bat --color always --decorations never --wrap never --language bash --paging never \
    | LESSHISTFILE=/dev/null less -R -L -Q -X -S --tilde --mouse $_LESS_HEADER -I --prompt "$_LESS_PROMPT" "$_LESS_CMDS"
}