Using the Linux Watch Command

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A somewhat lesser known linux command is watch. It will display the output of a regular command and update the screen if that output changes. Here are some helpful use cases.

Watch for directory contents changing

Try the command:

watch -d ls -la

You’ll see the output of ls -la and every 2 seconds the screen will refresh if there are any changes. If files grow in size, get removed, or added, you’ll see it highlighted on the screen when it happens.

The -d switch will highlight changes for you to make it easier to spot.

Watch disk space grow or shrink

Try this command:

watch -d df -h

You’ll see an output of the free disk space in human readable format and if it changes it will update live every 2 seconds.

More info

See man watch.

linux, misc