I've been dilgently working my way through Laura Lemay's book Sams Teach Yourself Perl in 21 Days, and doing all the exercises at each stage. Each time I would find a bug, I would stop and not continue until I'd solved it. I've now finished chapter (day) 8 and I'm unwilling to continue, as I'm stumped by a script called morenames.pl.

This script takes its input from a list of names in a text file which I called namefile.txt. It presents you with a menu to sort the names in alpha-betical order by firstname or surname, to search for a name in the file or to exit.

The 2 sorting parts and the exit part all work fine, however it is the search part that's giving me trouble. Here is a copy of the name list I made up;

namefile.txt

And here is a copy of the script;

morenames.pl

OK, so I run the script by typing morenames.pl namefile.txt in Linux or perl morenames.pl namefile.txt in Windows (I tested both) and choose option 3. When I get asked what to look for I type ch, but the output I get is all the names but with the names including lower case ch doubled. When I redo the test I get the correct output, but still in lower case only.


I would expect this second output the first time around. Note there is a line at the end of the loop @keys = (); Which is supposed to undefine keys for next search.

I would also expext to find Chris Gates in that list too. I tried using grep -i like I would in UNIX to ignore case sensitivity but Perl got very cross with me for doing this.  Evidently grep works differently in Perl than the way it does in UNIX. I also tried many lc and uc functions on the $name, $raw and $search variables but with no success.

So my questions are;
1. How can I change the script so that the search will be case insensitive?
2. Why does the script need 2 iterations to give me decent output?

I've searched the internet for fixes of this script and found none. I will probably find an answer to this in later chapters, but I'm stubborn and want to find this out before continuing with the info I have from the chapters until now.

BTW, I was using Perl 5.8.8 on BackTrack 2 , and ActiveState Perl 5.8.8 on Windows XP Pro if that interests anyone.

Thanks shakuni, you've been more help than you realise. Firstly the /i switch works great - Chris Gates has now been found. 

Your remark about the script working fine on your system, and it beeing a problem on my system got me thinking. The thing is I had tried this on both my home PC and on my laptop from work and got the same result, before posting here.

So I got to thinking about how I had been running the script and how you had probably run it. When I ran the script I would go through the menu in numerical order to make sure all the options worked. I then thought that you had only tried option 3 in the menu. I did some testing and I found that when choosing option 3 it works fine but when choosing option 2 (Sort names by first name) before option 3 the result would be the entire list and the chosen search string doubled.

I looked at the code and found that in the loop for option 2 the array @keys is used but it is not undefined before option 3 begins. Obviously in option 3 $search is being added to @keys and this is giving the result I was getting. I managed to solve this by moving @keys = (); to the top of the loop for option 3.

The script is now working perfectly. For all those that didn't understand what I wrote above and want to know, the loop for option 3 now looks like this;