Some strange application shipped created a bunch of tab-delimited files that had the column headings at the start of *every line*, instead of just having them as the first line/row in the file. Large, nasty files too (80-150 MB each). Perl to the rescue!

#!/usr/bin/perl
use strict;

my $file    = shift or die "Need a filename!\n";
my $columns = shift or die "How many columns?\n";
my $newfile = "$file.new";

open(F, "$file")     or die "Could not open $file: $!\n";
open(G, ">$newfile") or die "Could not create $newfile: $!\n";

## Set the first row as column headings:
print G join("\t", (split(/\t/,<F>,$columns+1))[0..$columns-1]), "\n";

## Rewind for the first line's data
seek(F,0,0);

## Now grab only the data from the rest:
print G (split(/\t/,$_,$columns+1))[$columns] while <F>;

close(F); close(G);

[download]

It took Perl about 40 seconds for a 100M file. I really love this language! :) It's so good at solving quick little problems like this (that might not have been so little in other languages...)

In reply to Nobody splits like Perl by turnstep

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