Dear fellow Monks,

The Unix uniq commands only removes adjacent identical lines. I was asked about a command that removes duplicates that are not adjacent, w/o sorting the file.

"No problems", I said, "a 5 line Perl script and you're done". But later it occurred to me - why 5 lines ? This will do the job: 

cat file1 file2 | perl -ne 'print if !(defined($foo{$_})); $foo{$_} = 
+1;' > out_file

[download]
So, how about making it even shorter ?

Note: my version is ungolfed for clarity
Note2: golf only the Perl code between 's, not the shell wrapper

In reply to (Golf) unique by spurperl

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