Need Help Writing a Package Script
 

I have designed a fairly generalized package script for Slackware 12.0. Now, what I want to do make one completely generalized build script. Here's what I have so far.
This is the config script for alsa-utils and you can see what alsa-lib would look like.
Not bad for my first script huh? But what I would like to do is pass in the name of a filename-version.tar.bz2 and have it automatically fill in the name and version. Can some one show me how to parse a string like that in a script?

Am I right in thinking you want to call:

gen_script alsa-utils-1.0.15.tar.bz2

If so, try:
This assumes that the name ends at a "-" followed by one or more numerics

and the version continues until .tar.bz2

Yes, you would be correct. Regular expression are confusing me to no end. I'm trying to use expr for the same purpose, but it doesn't seem to give me the correct result.
WTF? I'm so confused. I don't know what you wrote, but it looks alien to me. Could you please break it down a little for my pitiful human mind. Thank you so much.

First when you pass parameters into a script they come in as $1 $2 $3 etc

Therefore if you call: gen_script alsa-utils-1.0.15.tar.bz2

$1 will be equal to "alsa-utils-1.0.15.tar.bz2"

I am then passing this string to awk (stay with me)
the -F sets the delimiter to split a string into sections, we are using a multicharacter delimiter beginning with a "-" and followed by any number of nummerics Examples -0 -012345 would both match.

I am then printing the first section { print $1 }

Note this $1 is seperate from the $1 passed to our script as it is a part of the awk construct.

So now we have our name variable set.

The second line passes "alsa-utils-1.0.15.tar.bz2" to sed (string editor) twice, first to search for the $name and the "-" symbol and replace it with nothing sed "s/$name-//" and then to remove the tail part of the string ".tar.bz2" sed 's/.tar.bz2//'

I really must go to work now (or I'll be late).

Wow, thanks I will certainly have to put this stuff to the test.

Why don't you have a look at shilo's generic SlackBuild script(see the This is how I do it all sticky) or AlienBob's and rworkmans' scripts at SlackBuilds.org for some ideas. I could suggest that you just use my src2pkg program which obsoletes about 80% of all manually-written SlackBuilds, but I think you are wanting to learn to write bash scripts, so it would be very counter-productive for you to use it. Didn't think I would ever say that... If you just want to make good packages, lots of packages and easily, then do use it. I learned lots of shell language in the process of writing it.

Regex don't make any sense until you learn them, then you love them!

Here's a perl regex example for you.
$1 = name $2 = version.

Using bash/expr
Here's one more with no regex
3 small steps
1. remove everything after the last "-" (sets $name to this)
2. remove the $name + a "-" from the beginning ($version="1.0.15.tar.bz2" at this point)
3. remove the ".tar.bz2" from the end of version (setting $version to this)

Thanks for all your input guys. I'm finally starting to get the hang for regular expressions though I will have to clobber my way through a few more proplems before I can say I have really learned the well. I managed to write my own build script which I'm rather proud of. Here's the code.
What's nice about this script is that it gives the option for a more specific but far shorter build script. To give an example. Here's one I wrote for my ALSA driver.
So, my archive of source files looks fairly clean. Check it from and ls -l command.
I know it's not a script to brag about, but it's my first really helpful script I've made, and I wanted to share it. Tell me what you think about it.