Basic Process Tree with Teletype (Bash script)

proc_tree.sh

#! /usr/bin/env bash

declare c=0;

_PidTree()
{
    declare __pid="$1";
    shift || return 2;

    declare stat=(); readarray -td ' ' stat < "/proc/${__pid}/stat";
    declare cmd=(); readarray -td '' cmd < "/proc/${__pid}/cmdline";
    declare ty; ty="$( readlink -e "/proc/${__pid}/fd/0"; )";
    declare ppid="${stat[3]}";

    printf " [%s] [%6s | %-6s] TY=%-10s '%s' [%s]\n" "$(( c++ ))" "$__pid" "$ppid" "$ty" "${cmd[0]}" "${cmd[*]:1}";

    if [[ $__pid != 1 ]];
    then
        _PidTree "$ppid";
    fi
}

_Main()
{
    declare __pid="${1:-$$}";
    shift || return 2;

    printf '%s\n' '      PID     PPID';
    _PidTree "$__pid" | sort -rk 1,1;
}

_Main "$@";