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Move "Why Isn't it Doing Anything?" to an earlier episode #836

Bioscibrarian opened this Issue Aug 21, 2018 · 0 comments


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Bioscibrarian commented Aug 21, 2018

The note "Why Isn't it Doing Anything?" is introduced in Episode 6.
It describes how a command will wait for input if the user forgets to add a filename for a command to take action on.

The command used for an example is part of a piped setof commands. It is wc -l, without a filename given, so wc is waiting for input.

I think that shell novices might make this mistake earlier in the class--I know I did when I first learned bash commands.

It is possible to introduce "Why Isn't it Doing Anything?" as early as Episode 4 (Pipes and Filters):

  • The text in the lesson is:
    If we run wc -l instead of just wc, the output shows only the number of lines per file:
    $ wc -l *.pdb

  • Could we introduce "Why Isn't it Doing Anything?" here, and describe what would happen if the user just typed "wc -l" (without *.pdb)?

  • Then it might be useful to introduce Ctrl-Z or some other command-suspending intervention. I know this might be too much to introduce, but I have been a helper in sessions when at least one or two people have gotten "stuck" in a bash command that was waiting for input. Students need to know at some point how to suspend a command.

This is part of my Instructor Training Checkout, but it's also something I would like to see introduced a bit earlier in the lessons. -Thanks!
Pamela Shaw, Northwestern University

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