Watch – A Useful Linux Command You May Have Never Heard Of
Updated: November 9th, 2007
How many times did I want to watch a directory waiting for a file to appear in it? Constant ls, for example, quickly got boring. A quick Perl script that would reload ls every 5 seconds… yeah it works but it takes a while to type up, and often enough I'm too lazy for that. And then I found 'watch' – a utility that comes with most *nix distros. Look at this beauty [man watch]:
NAME
        watch – execute a program periodically, showing output fullscreen
SYNOPSIS
watch  [-dhvt]  [-n  ]  [–differences[=cumulative]]  [–help]
[–interval=] [–no-title] [–version]
DESCRIPTION
watch runs command repeatedly, displaying its output (the first screen
full).   This  allows you to watch the program output change over time.
By default, …
