in reply to remove lines from file ending with / char

Just supposing the problem was to find the smallest set of directories whose removal would not delete any files (the folded comments make it more difficult to read):

use feature ":5.14"; use warnings FATAL => qw(all); use strict; use Data::Dump qw(dump pp); sub findEmptyDirectories(&@) {package FindEmptyDirectories; my $R = shift; # Processing routine from us +er followed by file/directory names my $d = {}; # Simulated directory tree {for(@_) # Load directory tree with e +ach file {if (my @c = /([^\/]+)/g) # Get path components from f +ile name {my $f = pop @c unless /\/\Z/; # Get file name unless direc +tory my $c = $d; # Start of descent through d +irectory tree $c = $c->{dir}{$_} //= {} for @c; # Descend along each path co +mponent adding new nodes as necessary $c->{file}{$f}++ if defined $f; # Count files at this level +with this name } } } sub R($) # Descend tree to count file +s in each directory {my ($d) = @_; # Position in directory tree $d->{files} += &R($d->{dir}{$_}) for keys %{$d->{dir}}; # Count fi +les below this level $d->{files} += keys %{$d->{file}}; # plus files at this level } R($d); # Count files at each level sub r($$$) # Descend tree in in-order i +n order to perform user action on empty directories {my ($R, $d, $p) = @_; # User action, directory sub + tree, path to sub tree return $R->(@$p) unless $d->{files}; # No files below this direct +ory so perform user action and return &r($R, $d->{dir}{$_}, [@$p, $_]) for sort keys %{$d->{dir}}; # Els +e process lower levels in directory tree } r($R, $d, []); # Call user action on direct +ories with no files } findEmptyDirectories {say "/", join("/", @_), "/"} split /\n/, << 'END +'; /peter/john/lilly.pdf /john/peter/jill.pdf /jimmy/gill/a.txt /jimmy/gill/johnny/ /wilbur/yankee/ /wilbur/yankee/aaa/bbb/nnn/ /wilbur/yankee/aaa/ccc/nnn/ /wilbur/yankee/aaa/ccc/aaa.txt /lola/riley/jibmo/txt /lola/riley/jibmo.txt /rolly/polly/quebe.lst END


/jimmy/gill/johnny/ /wilbur/yankee/aaa/bbb/ /wilbur/yankee/aaa/ccc/nnn/