Have you ever wanted to run some command periodically, usually to wait for some change in the result (like waiting for some ACL to be propagated, a price value to change, etc)?
Seek no more! Do you know the "watch" unix command?
watch -n 60 <command>
This will run <command> every 60 seconds! And you can inspect the output every time it does.
Its usage is quite simple. The help output is:
Usage:
watch [options] command
Options:
-b, --beep beep if command has a non-zero exit
-c, --color interpret ANSI color and style sequences
-d, --differences[=<permanent>]
highlight changes between updates
-e, --errexit exit if command has a non-zero exit
-g, --chgexit exit when output from command changes
-n, --interval <secs> seconds to wait between updates
-p, --precise attempt run command in precise intervals
-t, --no-title turn off header
-x, --exec pass command to exec instead of "sh -c"
-h, --help display this help and exit
-v, --version output version information and exit
Useful command to know!
