watch-with-pipe.md

Watch with pipe

Sometimes the watch command acts weird if one tries to run a piped command within it. One might have tried things like:

What DOES NOT WORK

$ watch ls -la | wc -l

The above is wrong because the pipe would be interpeted by the shell between the watch and wc commands

$ watch bash -c 'ls -la | wc -l'

The above is still wrong. For some reason watch would remove the single quotes (maybe because its counted as a seperate argument?), so it would actually run watch 'bash -c ls -la | wc -l' which would return the wrong results, as it would ignore -la as it would think they are part of the flags for bash and not ls. (that might be related to my specific version of watch)

What WORKS

$ watch 'ls -la | wc -l'

And also by the same logic this also works:

$ watch "bash -c 'ls -la | wc -l'"