code loading in perl <progress-bar> - perl

Question

this perl code for loading
When running code
use Term::ProgressBar::IO;
open my $fh, '<', 'passwords.txt' or die "could not open file n.txt: $!";
my $pb = Term::ProgressBar::IO->new($fh);
my $line_count;
while (<$fh>) {
$line_count += 1;
$pb->update();
}
close $fh;
print "total lines $line_count"
C:\Users\USER\Desktop>r.pl
0% [* ]total lines 360
what is the problem

Answer 1

Term::ProgressBar::IO seems incompatible with regular filehandles, and expects an instance of IO::File as seen in the test script, so you'll want to define $fh with
my $fh = IO::File->new('passwords.txt', 'r') or die ...;
The docs say that this module will work with any seekable filehandle, but it still doesn't work (for me, anyway).
The relevant line during construction is:
if (ref($count) and $count->can("seek")) {
When $count is an IO::File type, this condition passes but it fails when $count is a regular GLOB, even one opened for reading and writing. A GLOB will support the seek method, but can("seek") won't return true until after a method has been called on it.
use feature 'say';
open my $fh, '<', 'some-file';
say $fh->can('seek'); # ""
say tell $fh; # 0
say $fh->can('seek'); # ""
say eval { $fh->tell }; # 0
say $fh->can('seek'); # 1
and this suggests another workaround (one that could be implemented inside Term::ProgressBar::IO to address this issue), and that is to make a filehandle method call on the filehandle before you pass it to Term::ProgressBar::IO:
open my $fh, '<', 'passwords.txt' or die "could not open file n.txt: $!";
eval { $fh->tell }; # endow $fh with methods detectable by UNIVERSAL::can
...

Answer 2

Here is a simple process bar code, output as below.
$n = 10;
for($i=1;$i<=$n;$i++){
proc_bar($i,$n);
select(undef, undef, undef, 0.2);
}
sub proc_bar{
local $| = 1;
my $i = $_[0] || return 0;
my $n = $_[1] || return 0;
print "\r [ ".("\032" x int(($i/$n)*50)).(" " x (50 - int(($i/$n)*50)))." ] ";
printf("%2.1f %%",$i/$n*100);
local $| = 0;
}