The Easter Bunny left you some code... 
use warnings;
use strict;

my $flag = 0;
while (<DATA>) {
    if (/^[^\t]/) {
        if (/^r145:/) {
            $flag = 1;
        }
        else {
            $flag = 0;
        }
    }
    print unless $flag;
}

__DATA__
c114: 0245, 0456, 1545 
    2555, 2444, 0344
    0444, 3434, 1434

r145: 0544, 0688, 2988 
    1332, 0221, 0867
    0655, 4548, 7463

c12: 2322, 0556, 3998 
    3545, 2002, 4500
    5650, 0830, 3324
    3433, 7070, 3404

[download]

Here is the output: 

c114: 0245, 0456, 1545 
    2555, 2444, 0344
    0444, 3434, 1434


c12: 2322, 0556, 3998 
    3545, 2002, 4500
    5650, 0830, 3324
    3433, 7070, 3404

[download]

In reply to Re: Regex: how to consider an unknown number of tabs? by toolic
in thread Regex: how to consider an unknown number of tabs? by Miraculix

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