Subject: Re: Using cd in scripts
From: John Kebbel (kebbelj@irwin.vetrol.com)
Date: Thu Jun 15 2000 - 16:59:32 MDT
Thanks, the alias suggestion from you and Ed solved my one-line jump
from here to there problem.
Your source tip was great also. I tried a little two-line program with
it and it worked fine.
Thanks again.
yellowdog-general@lists.yellowdoglinux.com wrote:
>
> JBS> So, when you run a shell script (or a Perl script, or whatever) that
> JBS> changes your CWD, it changes it within the context of that process, and
> JBS> when that process exits, and you return to the shell
>
> Just in case this wasn't obvious: When you run a shell script, you are in
> fact starting a new process, which runs the commands in the script file, and
> then exits. This may not be how .BAT scripts work in DOS (I don't actually
> know DOS, so I'm not sure).
>
> There's another thing you can do: You can use the 'source' command to run
> the commands in a file, within the context of the current process (i.e. it
> does not create a new process). So given a file commands.txt containing
>
> cd /var/tmp
> touch foo
>
> if you do
>
> bash% ./commands.txt
>
> to run the script, it will create a new shell process, which will change to
> /var/tmp, touch a file called foo, and then exit, returning you to whatever
> directory you were in when you ran the script. Whereas if you do
>
> bash% source commands.txt
>
> it will do the same thing, but without creating a new shell (i.e. within the
> context of your current shell), so it'll leave your current shell in
> /var/tmp when you're done.
>
> Which one you want depends on exactly what effect you're trying to
> accomplish. :^) Aliases are better if you only want to run one command, but
> if you need to do more than one thing at a time, you can write a script that
> you source rather than executing. And you can combine these two, e.g.
>
> alias dostuff='source $HOME/bin/stuff-to-do.txt'
>
> will let you run a bunch of commands in the context of your current shell
> with a single command.
>
> -Josh (irilyth@infersys.com)
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