How to write a Perl script that can count and display unique line?

Question

How to write a perl script that can read every line from a file and count how many times each unique line was found.

Answer 1

perl -e 'while (<>) {chomp; $z{$_}++;} while(($k,$v) = each(%z)) {print "$v\t$k\n";}' filetoscan.txt



Or, just do this instead:



cat filetoscan.txt | sort | uniq -c | sort -n

Answer 2

That question is a bit complex and requires a long answer. Best bet look at some examples of Perl on google. Perl is a very powerful scripting language and can be used for things like that.



Good Luck

Answer 3

Perl Uniq

Answer 4

The loop from the example above can be eliminated with the -n switch. Printing can be written simpler too:



perl -ne '{chop; $u{$_}++;} END {print $u{$_}."\t".$_."\n" for keys %u}' filetoscan.txt

Answer 5

answers.google.com