Perl can't find file - perl

Question

I am a relatively infrequent user of Perl. I have written a script that takes two input files with the same name but different extensions, processes them and outputs a third file. It works when I specify the name of the file, but I want it to search for all relevant files in a directory and process all of them. However, when I do this it keeps saying there is no such file or directory - even though I'm sure there is. I've looked at all the relevant pages on this site and tried the suggestions there, but it still doesn't work. I'm stumped.
Here is the code, missing the processing of the files themselves, as that is long and not relevant.
use strict;
use warnings;
use autodie;
#specify single file - works when this is not commented and the loops below are
#my $file = "BE_Read01_f2-2";
#on a Mac
my $dir = "/Users/sashacalhoun/Documents/supervision/tariq/Syllables";
opendir(my $dh, $dir);
while (my $file = readdir($dh)) {
if($file=~s/(.+-CV)\.TextGrid/$1/) {
print "$file\n";
open(my $syl, "<", "$dir/${file}.par");
while(my $line=<$syl>) {
#processes this file - not included
}
close($syl);
my $gridfile = "$file-CV.TextGrid";
my $outfile = "$file-syl.TextGrid";
open(my $grid, "<", $gridfile);
open(my $out, ">", $outfile);
while(my $line=<$grid>) {
print $out $line;
# other processing of this file
}
close($grid);
close($out);
}
}
It says: Can't open '/Users/sashacalhoun/Documents/supervision/tariq/Syllables/BE_Read01_f2-1-CV.par' for reading: 'No such file or directory' at ./get_syl.pl line 36
Thanks very much for your help.

Answer 1

From your error message, it is apparent that the line causing the error is this line:
open(my $syl, "<", "$dir/${file}.par");
it keeps saying there is no such file or directory - even though I'm sure there is.
You can prove to yourself that no such file exists by copying the path in the error message:
Can't open
'/Users/sashacalhoun/Documents/supervision/tariq/Syllables/BE_Read01_f2-1-CV.par'
for reading: 'No such file or directory' at ./get_syl.pl line 36
and doing this:
$ ls /Users/sashacalhoun/Documents/supervision/tariq/Syllables/BE_Read01_f2-1-CV.par
And, instead of constructing paths yourself, you should consider using File::Spec, etc.:
use File::Spec::Functions;
my $path = catfile $dirname, $fname;
And, you should probably check whether the filename is a file or directory before constructing your path:
if (-f $path -r $path) { #then it's a file that is readable...
#Here you might want to skip files whose names start with a '.', i.e. hidden files
}
And, your debugging print statement should be this:
my $path = "$dir/$file.par";
print "$path\n";
open(my $syl, "<", "$path.par");
By the way, if you don't like typing \n after every print statement, you can use say():
say "After printing this text, perl automatically adds a '\n' to the end of the output";
You do have to employ a use statement for say() to work, e.g.
use 5.010;
And, you should add a die() clause to your opendir()/open() statements:
opendir(my $DIR, $dir)
or die "Couldn't open $dir: $!";