I was searching for a way to make some kind of a live memory usage monitoring in Linux when I found watch. I wonder why didn’t I ever knew about it! It’s damn useful! You can monitor literally everything with watch.

Here are some scenarios you may use if for:

Watch for changes in a directory:

$ watch ls -la

Watch for any Java program being started/stopped:

$ watch -n 1 "ps ax | grep java"

I used watch for memory usage monitoring:

$ watch -n 1 free -m

$ watch -n 1 cat /proc/meminfo