Show memory usage of commands you run in terminal, including sub processes and even supports pipes

mmmon.sh

#!/bin/bash
# this script allows you to monitor the memory usage of a command like
# mmmon.sh "docker save my/image:0.1 | xdelta3 -d -s /dev/stdin delta-0.1-to-0.2.xdelta /dev/stdout | docker load"
# the ""'s are important
# it will include any child processes
# it will handle ctrl+c and forward it
# I couldn't find this anywhere else, hope someone finds it useful
# - Gabriel
# licence: public domain

# Check if a complex command is provided
if [ -z "$1" ]; then
  echo "Usage: $0 'complex-command'"
  exit 1
fi

# Function to forward the SIGINT signal to subprocesses
forward_sigint() {
  for pid in $(echo "$all_pids" | tr ',' ' '); do
    kill -s SIGINT "$pid" 2>/dev/null
  done
  exit 0
}

# Run the complex command in the background
eval "$1 &"

# Get the PID of the most recent background command
PID=$!

# Set up the trap to handle the SIGINT signal
trap forward_sigint SIGINT

# Function to get all related PIDs
get_related_pids() {
  local pids="$1"
  local new_pids="$(pgrep -P $(echo "$pids" | tr '\n' ',' | sed 's/,$//') | tr '\n' ' ')"
  echo "$pids $new_pids"
}

# Monitor memory usage of the PID and its children
while kill -0 "$PID" 2>/dev/null; do
  echo "Monitoring memory usage (PID, PPID, COMMAND, %MEM, RSS):"
  pids="$(get_related_pids "$PID")"
  siblings="$(pgrep -s "$(ps -o sid= -p "$PID")")"
  all_pids="$(echo "$pids $siblings" | tr ' ' '\n' | sort -u | tr '\n' ',' | sed 's/,$//'| sed 's/^,//')"
  ps_output=$(ps -o pid,ppid,comm,%mem,rss --forest -p "$all_pids" | grep -vE '^ *$|^ *PID')
  echo "$ps_output"
  echo "-------------------------"
  total_memory=$(echo "$ps_output" | awk '{sum += $5} END {print sum}')
  echo "Total memory (RSS): $total_memory"
  echo "-------------------------"
  sleep 1
done