history_counter.pl

#!/Users/brian/bin/perl
use v5.36;
use open qw(:std :utf8);
use utf8;

use File::Basename;
use Text::Shellwords qw(shellwords);

=head1 NAME

history_counter.pl - count the commands I use in my shell

=head1 SYNOPSIS

	% history | perl history_counter.pl
	 212 perl
	 210 git
	 175 cd
	 159 ls
	  82 make

=head1 DESCRIPTION

This program counts the number of times I've used a particular command
in my shell history. It's smart enough to recognize multiple commands on
one line if I used pipelines or compound commands (C<&&>, C<||>, and C<;>).

This works with B<bash> and B<zsh>, which assume that a line from B<history>
has a command number and then the command:

	% history
	3024  history | perl -F'\s+' -le 'print $F[2]' | sort | uniq -c | sort -nr | head -5
	3025  history | perl history.pl | head -5
	3026  zsh
	3027  history

=head1 AUTHOR

brian d foy, C<< <briandfoy@pobox.com> >>

=head1 COPYRIGHT & LICENSE

This program is available under the Artistic License 2.0,
L<https://opensource.org/license/artistic-license-2-0-php/>

=cut

my %Commands;
LINE: while( <> ) {
	chomp;
	my @words = shellwords $_;

	# get rid of the line number
	shift @words;

	# some command lines are invalid, like unbalanced quotes
	# In that case, shellwords returns a single element.
	next LINE unless @words;

	my @line_commands = [];
	TOKEN: while( my $token = shift @words ) {
		state %command_separators = map { $_ => 1 } qw( || && | ; );
		if( exists $command_separators{$token} ) {
			push @line_commands, [];
			next TOKEN;
			}

		push $line_commands[-1]->@*, $token;
		}

	my @bins = map { $_->[0] } @line_commands;
	foreach my $bin ( @bins ) { $Commands{$bin}++ }
	}

foreach my $bin ( sort { $Commands{$b} <=> $Commands{$a} } keys %Commands ) {
	printf "%4d %s\n", $Commands{$bin}, $bin;
	}