Modify Perl script to run for each file with specified extension in a given directory - perl

Question

I need to modify a Perl script x937.pl to run on all files with extension .x937 within a specific directory. Currently, I use a separate script test.pl that calls my main script, and runs it for each file of that type. However, I need to combine both into one script.
Ideally, I would be able to specify a directory path in the script, and loop through all *.x937 files in that directory.
test.pl
#!/usr/bin/perl -w
use strict;
use Encode;
my #files = <*.x937>;
foreach my $file (#files) {
system('x937.pl', $file);
}
x937.pl
#!/usr/bin/perl -w
use strict;
use Encode;
use warnings;
my $tiff_flag = 0;
my $count = 0;
my $file = "output_$ARGV[0].txt";
unless ( open OPUT, '>' . $file ) {
die "Unable to create $file";
}
open FILE, '<:raw', $ARGV[0] or die "Error opening '$ARGV[0]' $!";
binmode( FILE ) or die 'Error setting binary mode on input file';
while ( read( FILE, $_, 4 ) ) {
my $rec_len = unpack( "N", $_ );
die "Bad record length: $rec_len" unless ( $rec_len > 0 );
read( FILE, $_, $rec_len );
if ( substr( $_, 0, 2 ) eq "\xF5\xF2" ) {
if ( $tiff_flag ) {
$count++;
open( TIFF, '>', 'output_' . $ARGV[0] . '_img' . sprintf( "%04d", $count ) . '.tiff' )
or die "Can't create image file $!";
binmode( TIFF ) or die 'Error setting binary mode on image file';
print TIFF substr( $_, 117 );
close TIFF;
}
$_ = substr( $_, 0, 117 );
}
print OPUT decode( 'cp1047', $_ ) . "\n";
}
close FILE;
close OPUT;

Answer 1

I think I managed to generate this correctly (on iPad, sat on the sofa) ... There could be some typos ; )
Usage: perl test_x397.pl <path>
test_x397.pl
#!/usr/bin/perl -w
use strict; use warnings;
use Encode;
my ($path) = #ARGV;
$path // die "No path specified";
(-e $path) or die "Path not found: $path";
(-d $path) or die "Not a directory: $path";
my #files = <$path/*.x937>;
foreach my $file (#files) {
process($file);
}
sub process {
my ($fname) = #_;
my ($dir, $file) = $fname =~ m{^(.*)/(.+)$};
my $tiff_flag = 0;
my $count = 0;
my $outfile = sprintf("%s/output_%s.txt", $dir, $file);
open (my $outfh, '>', $outfile) or die "Unable to create $outfile. $!";
open (my $infh, '<:raw', $file) or die "Error opening '$file'. $!";
my $buffer = undef;
while (read ($infh,$buffer,4)) {
my $rec_len = unpack("N", $buffer);
die "Bad record length: $rec_len" unless ($rec_len > 0);
read ($infh, $buffer, $rec_len);
if (substr($buffer, 0, 2) eq "\xF5\xF2") {
if ($tiff_flag) {
$count++;
my $tiff_filename = sprintf('%s/output_%s_img%04d.tiff', $dir, $file, $count);
open (my $tiffh, '>', $tiff_filename) or die "Can't create image file $!";
binmode($tiffh) or die 'Error setting binary mode on image file';
print $tiffh substr($buffer, 117);
close $tiffh;
}
$buffer = substr($buffer, 0, 117);
}
print $outfh decode ('cp1047', $buffer) . "\n";
}
close $infh;
close $outfh;
}
A few things to note:
Always use the three argument version of open
Using a scalar filehandle makes it easier to pass it around (not necessary in this example but good practice)
Don't modify $_. It can lead to nasty surprises in larger programs
You already used sprintf to make part of your tiff filename, so why not use it for the whole thing.