use strict;
use warnings;

my @data = qw{
   /path/some/random/file
   /home/mary/projectA/reports/rep1.prn
   /usr/man/man1/brewcoffee.1
   /home/fred/projects/cv.prn
   /home/bill/work/prog.c
   };

my @arr =
   sort
   map { join q{/}, ( split m{/} )[ 0, 1 ] }
   @data;

print qq{$_\n} for @arr;
print q{-} x 20, qq{\n};

@arr =
   sort
   map { join q{/}, ( split m{/} )[ 0 .. 2 ] }
   @data;

print qq{$_\n} for @arr;
print q{-} x 20, qq{\n};

@arr =
   sort
   map { $_->[ 4 ] =~ s{.prn$}{}i ; join q{/}, @$_ }
   map { [ split m{/} ] }
   @data;

print qq{$_\n} for @arr;
print q{-} x 20, qq{\n};

@arr =
   sort
   map { $_->[ -1 ] =~ s{.prn$}{}i ; join q{/}, @$_ }
   map { [ split m{/} ] }
   @data;

print qq{$_\n} for @arr;
print q{-} x 20, qq{\n};