copy line with character

jalopez453 has asked for the wisdom of the Perl Monks concerning the following question:

Hello everyone, I am looking for a little help on my code here. I want to copy the lines that have the letter M in the first column but not sure what I am doing wrong or what is missing. I am very new to perl, so I apologize for this very basic request. Thank you in advance for the help

use strict;

my $find = 'M';

    open (NEW, ">", "output.txt" ) or die "could not open:$!";

    open (FILE, "<", "Report.txt") or die "could not open:$!";

        while (<FILE>) {
        print NEW if (/$find/);
    }
close (FILE);
close (NEW);
[download]

Comment on copy line with character Download Code

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Re: copy line with character by stevieb (Canon) on Nov 23, 2015 at 18:41 UTC
Hi jalopez453, welcome to the Monastery! When asking a question of PerlMonks, please provide us some of your sample input data, and what your expected output would look like (both in `<code></code>` tags as you've done with your actual code). I suspect what you're getting as output are all lines that contain `M`, but anywhere in the string, not just at the beginning. What you need to do is specify in your regex that you ONLY want to match if an `M` is at the start of your string. You do this by using the caret, aka `^` at the beginning of your regex: `my $find = '^M';` [download] After that change is made, using this data: `no M at start M at start M at start again another line, no M at start` [download] I get this output: `M at start M at start again` [download]	[reply] [d/l] [select]
Re^2: copy line with character by jalopez453 (Acolyte) on Nov 23, 2015 at 18:54 UTC
Sorry about that. For the next questions I have I will remember to include a sample of my input file. Thank you so much for the quick response this is exactly what I was wanting to accomplish!	[reply]
Re^3: copy line with character by jalopez453 (Acolyte) on Nov 23, 2015 at 19:24 UTC
If you are still available, I do have another question? :) If I want to include the second line after the line containing M and wrap it all into one line on the output file what would I have to include? `sample of input file: M12345678 John Doe 11/20/15 M987654 REJECTED FAILED --------------------------------------------- sample of output file: M12345678 John Doe 11/20/15 M987654 REJECTED FAILED use strict; my $find = '^M'; open (NEW, ">", "output.txt" ) or die "could not open:$!"; open (FILE, "<", "Report.txt") or die "could not open:$!"; while (<FILE>) { print NEW if (/$find/); } close (FILE); close (NEW);` [download]	[reply] [d/l]
Re^4: copy line with character by stevieb (Canon) on Nov 23, 2015 at 19:37 UTC
Re^5: copy line with character by jalopez453 (Acolyte) on Nov 23, 2015 at 20:24 UTC
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Re^4: copy line with character by BillKSmith (Monsignor) on Nov 23, 2015 at 20:44 UTC
Re^5: copy line with character by jalopez453 (Acolyte) on Nov 23, 2015 at 20:55 UTC
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