Re: Two sequential help requests

[Eric Blake]

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According to Robert Carroll on 10/8/2008 3:21 PM:
> If I type ls --help (or the other GNU commands I have tried) I get a
> help listing.  However if I type the same sequence again I see the
> command line erased on hitting ENTER.  If, after the first command
> completes, I hit ENTER and then re-enter the command, it does provide
> the help listing. I am using the last UBUNTU release (Hardy Heron).
> Perhaps this behavior is what was intended since someone might argue
> that it is not necessary to issue the same command twice, but this could
> also be a bug.

Thanks for the report.  I'm not completely sure I follow what you are
complaining about; however, I don't think it is an actual bug in ls, but a
misunderstanding on your part about how the shell works.  Can you copy and
paste the lines from your terminal that show the behavior you are worried
about?  ls is not stateful: there is no way that one invocation of 'ls
- --help' can affect how the next process behaves.

Perhaps what is happening is that the command is indeed being executed
twice, but because it gives identical output, so it appears that nothing
has changed in your display.  Using a blank 'ENTER' forces an empty
command and the shell prints an extra prompt, so that you can see the
difference in output.  Depending on your shell, you can also configure the
prompt to include a command sequence id, to make it obvious by the change
in a prompt that consecutive commands have indeed resulted in otherwise
identical output.

- --
Don't work too hard, make some time for fun as well!

Eric Blake             address@hidden
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