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Re: Quick question



On Wednesday 03 January 2007 09:00, Gregor Schneider wrote:
> Hi guys,
>
> just a short question:
>
> After installing Edge, I see the common-user-$PS1 as follows:
>
> ${debian_chroot:+($debian_chroot)}\u@\h:\w\$
>
> I understand \u@\h:\w\$, however, what does
>
> ${debian_chroot:+($debian_chroot)}
>
> do?

From the bash manpage under the "Parameter Expansion" section:

  ${parameter:+word}
      Use  Alternate  Value.   If parameter is null or
      unset, nothing is substituted, otherwise the
      expansion of word is substituted.

Basically, this is to show info about the current chroot you are in. This is 
useful for when you have various chroots (say for different debian 
versions, etc).

The value gets pulled from the environment, or from /etc/debian_chroot. See 
this part of /etc/bash.bashrc:
# set variable identifying the chroot you work in (used in the prompt below)
if [ -z "$debian_chroot" ] && [ -r /etc/debian_chroot ]; then
    debian_chroot=$(cat /etc/debian_chroot)
fi

-- 
Wesley J. Landaker <wjl@icecavern.net> <xmpp:wjl@icecavern.net>
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