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Is it possible to write a Perl one-liner to get difference between two files?

Posted on 2009-07-13
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Last Modified: 2012-05-07
Have two files test1.txt and test2.txt
test1.txt
AA-A123
AABBCC
123_ABC
XYZ-A01
.....
test2.txt
123_ABC
AABBCC
AA-A123
....
Want to get test1.txt subtracts test2.txt , i.e.
XYZ-A01
You can assume that test2.txt is a part of test1.txt but the order is not necessarily same.
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Question by:jl66
3 Comments
 
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Assisted Solution

by:Adam314
Adam314 earned 150 total points
ID: 24840280
Not a 1-liner, but this works....
##### Remove file1 from @ARGV (process file2 first)
my $f2=shift(@ARGV);
 
##### Read file2
my %file2;
while(<>) {
	chomp;
	$file2{$_}++;
}
 
push @ARGV, $f2;
while(<>) {
	chomp;
	next if $file2{$_};
	print "$_\n";
}

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Accepted Solution

by:
ozo earned 350 total points
ID: 24841645
perl -ne "print unless $s{$_}++||@ARGV" test2.txt test1.txt
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Author Comment

by:jl66
ID: 24856801
Thank both of you very much. I will verify the solutions later.
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