Here's one option:
use strict;
use warnings;
use File::Slurp qw/read_file/;
my ( %file1Hash, %file2Hash, %mergedHash );
my @files = sort { -M $a <=> -M $b } <"*.txt">;
do { chomp; $file1Hash{$_}++ }
for read_file $files[0];
$mergedHash{$_}++ for keys %file1Hash;
do { chomp; $file2Hash{$_}++ }
for read_file $files[1];
$mergedHash{$_}++ for keys %file2Hash;
print "$_\n" for grep $mergedHash{$_} == 1, keys %mergedHash;
What it does:
do { chomp; $file1Hash{$_}++ } for read_file $files[0];
^ ^ ^ ^
| | | |
| | | + - Read the file, returning a
+list
| | + - Do this for each line
| + - Make the line a hash key and increment the asso
+ciated value
+ - Remove the newline
$mergedHash{$_}++ for keys %file1Hash;
^ ^
| |
| + - Do this for each key
+ - Make the line a hash key and increment the associated value
print "$_\n" for grep $mergedHash{$_} == 1, keys %mergedHash;
^ ^
| |
| + - If it only appears once (in
+ either file, but not both)
+ - Print the line
This uses a hash to tally identical lines, then shows only those keys (lines) whose value is 1, i.e., lines which only appear once in either file.
Hope this helps!
Update: Used three hashes: one for each file, and one merging the two hashes, in case the same line is repeated twice within a file--and those lines are only in that one file.
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