MemImpact

MemImpact is a lightweight, Rust-powered CLI tool that measures the maximum memory usage of any terminal command — including all of its child processes.
It works similarly to the classic Unix time command, but focuses specifically on memory.

Perfect for easy benchmarking, profiling, or simply understanding how much RAM your commands actually consume.

Features

• Measures peak memory usage (RSS) of any command
• Includes memory from child processes
• Works on any Linux (uses /proc/<pid>/status)
• Fast, zero external dependencies, written in pure Rust std
• Works as a direct command or with an optional shell wrapper
• Easy to install
• Easy to use, just add memimpact in front of your command

Installation

Option 1 - Install via Cargo

cargo install --git https://github.com/mifour/memimpact

or

cargo install memimpact

Option 2 — Download a Prebuilt Binary

Go to:

GitHub Releases → Latest → Assets

Download and install:

chmod +x memimpact
sudo mv memimpact /usr/local/bin/

Optional: Add a memimpact shell wrapper

If you'd like a time-like interface, add this to your .bashrc or .zshrc:

memimpact() {
  "$@" &
  pid=$!
  /path/to/memimpact --final $pid # &
  wait $pid
}

Usage

help

➜ ./memimpact --help            
Memimpact -- measure the memory impact of any PID and its children processes.
Version: 0.0.1
Usage: memimpact <options> <pid>
Options:
--hertz int, the desired number of iterations per second
Flags:
--final, display only 1 line with the max value

Basic usage

Using the optional shell wrapper

./memimpact 115404
Tracking memory usage of PID 115404 (spotify)
PID 115404 (spotify): current 411MB, max 411MB
PID 115404 (spotify): current 406MB, max 411MB
...

Example:

memimpact rg -c -o '[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,3}' data.csv

Output example:

[2] 183480
39799522
[2]  + 183480 done       "$@"
PID 183480 (rg): max 3GB

How It Works

1. Spawns your command as a child process
2. Monitors /proc/<pid>/status (and any child PIDs)
3. Tracks the peak RSS over the lifetime of the process
4. Prints a summary

No kernel modules, no ptrace, no dependencies — just reading /proc.

Contributing

Contributions, issues, and feature requests are welcome! Feel free to open a PR or issue.

License

MIT License

Copyright (c) 2025, Mifour

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.