How reliable/portable are Nix built-ins/commands (echo, ps, sort, uniq) from Debian to other distros

Question

I've coded a script and am wondering about it's reliability / portability.

#!/bin/bash
threadsPlease() {
  ps -mo lwp,c -p $1 | sort -gk 2 | uniq -f 1 
}

THREAD_LINE=$( threadsPlease $1 | grep -v - | tail -1)

THREAD10=$(echo $THREAD_LINE | awk '{print $1}')
THREAD16=$(printf '%x\n' $THREAD10)

JAVA_LINE=$(jstack $1 | grep $THREAD16)
echo "OS data (thread, CPU usage %): " $THREAD_LINE
echo "Java thread: " $JAVA_LINE

Script displays system and Java thread data, given Java PID. Sample execution:

./whichThreadIsIt.sh 6814
OS data (thread, CPU usage %):  6838 3
Java thread:  "AWT-EventQueue-0" #19 prio=6 os_prio=0 tid=0x00007f50f4090800 nid=0x1ab6 waiting on condition [0x00007f510dfbb000]

Q1: Aside from the obvious ("jstack/java/awk/... is not available or not in path" or "input data given wrongly"), when this will not work the intended way (Ubuntu/Debian)?

Q2: "It's easier to port a shell, than a shell-script", my friend likes to say. So, how much more effort this would need to work in Fedora / CentOS, Free BSD and Solaris? Am I wrong expecting it to run without troubles (assuming Bash present on those boxes)?

Answer 1

#!/usr/bin/env bash

May or may not increase the portability, as if bash is actually installed on a *BSD system, it usually exists at /usr/local/bin/bash. However, env may not be portable, though that would only be for really old or weird unix systems.

ps is an especially not-portable command, especially if you intend to use BSD/GNUisms on a SysV system (e.g. Solaris). Installing the GNU tools somewhere and then fixing PATH to include those would be one solution.