watch¶
Execute command at regular intervals. It also shows the output of every run.
$ watch -n <SECONDS> <YOUR COMMAND TO EXECUTE>
$ watch -n 1 date
-t -> Turn off the header showing the interval.
-d -> Highlight the differences between successive updates.
More: www.baeldung.com/linux/watch-command
Save outputs to a file with date (Example)¶
You can do something like below to run your command every second and save all outputs to a file with execution date on top while still printing output to screen:
$ watch -n 1 'echo -e "- $(date)\n$(YOUR COMMAND)\n" | tee -a outputs.txt'
You may use
freeforYOUR COMMANDto see how it works.
Pay attention to usage of single quotes and double quotes
We don't want to execute date and YOUR COMMAND before passing them to watch command.
Instead, we want them to be executed by watch command. Therefore we use single quotes to pass
our command as literal string to watch.
More: Single vs Double Quotes
The output will be something like this:
- Sun May 19 12:44:00 AM +03 2024
<YOUR COMMAND OUTPUT>
- Sun May 19 12:44:01 AM +03 2024
<YOUR COMMAND OUTPUT>
- Sun May 19 12:44:02 AM +03 2024
<YOUR COMMAND OUTPUT>