Re: How to handle the error when we try to read an empty text file in perl

[Discipulus]

Hello ppp,
i think your assumption is wrong: Perl does not complain for an empty file

use strict;
use warnings;

open my $fh, '<', 'C:\scripts\vacuum.txt', or die "Could not open file
+ $!";
    while (my $line = <$fh>)
    {   
              print "line $. reading '$line'\n";
             
    }
#update: removed nonsense part as pointed by BrowserUk below

You must have some other issue like permission, path or other.

Anyway you can test the size of a file with file test operators:

-e  File exists.
-z  File has zero size (is empty).
-s  File has nonzero size (returns size in bytes).

>perl -we "use strict; my $file = 'c:\scripts\vacuum.txt'; if (-e -s $
+file){print qq(it exists and has not zero lenght\n)} else {print qq(e
+xists but zero lenght\n)}"
exists but zero lenght

>perl -we "use strict; my $file = 'c:\scripts\002.txt'; if (-e -s $fil
+e){print qq(it exists and has not z
ero lenght\n)} else {print qq(exists but zero lenght\n)}"
it exists and has not zero lenght

Also see sysopen to have a more granular approach opening files

HtH
L*

[ppp]

Hii thansk for answer plese see the updated question.

[soonix]

I mean if file is empty then it should add the $address in ppp.txt's first line otherwise go to the while loop

in this case, rewording and expanding Discipulus' example:

my $file = 'C:\ppp.txt';
print "file '$file' ";
if (-e $file) {
    print 'exists ';
    if (-z $file) {
        print 'but is empty';
    } else {
        print 'and is not empty';
    }
} else {
    print q!doesn't exist!;
}
print "\n";

you would have to move your code in like this (untested):

my $file = 'C:/ppp.txt';
print "file '$file' ";
if (-e $file) {
    print 'exists ';
    if (-z $file) {
         # print 'but is empty';
         my $fh, '>>', $file, or die "Could not open file '$file' for 
+appending: $!";
                 print$fh $address . ' or whatever you want';
                 close $fh;
    } else {
         # print 'and is not empty';
                 ... (your "old" open and while loop)
    }
} else {
    # print q!doesn't exist!;
        ... (either create it or print error message)
}
print "\n";