uniq -c option

When I want to count the number of redundant words in a file (hoge.txt), I have used simple Perl code like this(count.pl).

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#!/usr/bin/perl
while(<>) {
        my($word) = split;
        $num{$word}++;
}
foreach (sort keys %num) {
        print "$_\t$num{$_}\n";
}

In order to count the number of redundancy in the list, I often run this script with shell command like below.

cat hoge.txt \
| perl count.pl \
| sort -rn

This operation can be relaced with a simple shell command like below.

uniq -c hoge.txt \
| sort -rn

uniq has been very familiar command, but I have not realized the option -c. The UNIX world is very deep indeed!

Written by bonohu in shell on 金 23 3月 2018.