[Discuss] What the use of .bashrc

[gaf at blu.org (Jerry Feldman)]

I generally use "Learning the BASH Shell" as a reference, but here is
the definition:
http://www.gnu.org/software/bash/manual/bashref.html#Shell-Parameter-Expansion



On 10/30/2012 11:46 AM, John Abreau wrote:
> I just looked for that in the bash manpage, and i can't find anything
> describing
> that behavior. Can you highlight where you discovered that?
>
>
>
> On Tue, Oct 30, 2012 at 11:07 AM, Jerry Feldman <gaf at blu.org> wrote:
>> On 10/30/2012 10:58 AM, joe at polcari.com wrote:
>>>   Looks to me like the first test only tests if $1 is not at the end of $PATHor am I missing something?    ----- Original Message -----From: &quot;Jerry Feldman&quot; >;gaf at blu.org
>>>
>> No, it tests is $1 exists in $PATH.
>> I really hate bash pattern matching because I have to read the manual
>> every time I use them.
>> in this case '*:"$1":*' looks for $1 anywhere in $PATH.
>
>
Look at expressions. A path is delimited by colons. So, this means look
for $1 anywhere in a path. You can easily test it. I have not looked at
some of the boundary cases, but they appear to work since I've been
using this for years.

    case ":${PATH}:" in
        *:"$1":*)
            ;;
Note that $PATH is prepended and appended by ':'. So, assume a PATH is
$HOME/bin/usr/bin, the pattern is ":$HOME/bin:/usr/bin:"
So, it will look for $1 anywhere between 2 colons.
http://www.gnu.org/software/bash/manual/bashref.html#Shell-Parameter-Expansion


-- 
Jerry Feldman <gaf at blu.org>
Boston Linux and Unix
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