Perl ABC

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2. Operators
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3. File test
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4. here

Get the file size

To get the file size , use the file test operator "-s".

-s $file

The unit of file size is bytes.

Example program

This is an example to get the file size using the file test operator -s.

use strict;
use warnings;

# Get the size of the file.
# -s filename
# Units are bytes.

print "1: Get the size of the file. -S\n";
my $file = "a.txt";
if (-f $file) {
  my $file_size = -s $file;
  print "The file size of $file is $file_size bytes.\n\n";
}
else {print "$file did not exist.\n\n"}

use strict;
use warnings;

print "2: Stop printing when the file size exceeds a certain byte.\n";

my $file = "output_$$. txt";
if (-e $file) {
  die "$file exists.\n";
}

open my $fh, ">", $file
  or die "File open error:$!";

while (-s $file < 1_000_000) {
  my $string = ('a' x 99) . "\n";
  print $fh $string;
}

print "The file size of $file after output is". -S $file. "Bytes.\n";

close $fh;

If the file size exceeds 1,000,000 bytes using while statement, it is stopped.