truncate all lines in a file while preserving whole words - perl

Question

I'm trying to shorten each line of a file to 96 characters while preserving whole words. If a line is under or equal to 96 chars, I want to do nothing with that line. If it over 96 chars, I want it cut it down to the closest amount less than 96 while preserving whole words. When I run this code, I get a blank file.
use Text::Autoformat;
use strict;
use warnings;
#open the file
my $filename = $ARGV[0]; # store the 1st argument into the variable
open my $file, '<', $filename;
open my $fileout, '>>', $filename.96;
my #file = <$file>; #each line of the file into an array
while (my $line = <$file>) {
chomp $line;
foreach (#file) {
#######
sub truncate($$) {
my ( $line, $max ) = #_;
# always do nothing if already short enough
( length( $line ) <= $max ) and return $line;
# forced to chop a word anyway
if ( $line =~ /\s/ ) {
return substr( $line, 0, $max );
}
# otherwise truncate on word boundary
$line =~ s/\S+$// and return $line;
die; # unreachable
}
#######
my $truncated = &truncate($line,96);
print $fileout "$truncated\n";
}
}
close($file);
close($fileout);

Answer 1

You have no output because you have no input.
1. my #file = <$file>; #each line of the file into an array
2. while (my $line = <$file>) { ...
The <$file> operation line 1 is in list context "consumes" all the input and loads it into #file. The <$file> operation in line 2 has no more input to read, so the while loop does not execute.
You either want to stream from the filehandle
# don't call #file = <$file>
while (my $line = <$file>) {
chomp $line;
my $truncated = &truncate($line, 96);
...
}
Or read from the array of file contents
my #file = <$file>;
foreach my $line (#file) {
chomp $line;
my $truncated = &truncate($line, 96);
...
}
If the input is large, the former format has the advantage of just loading a single line into memory at a time.