How i create a file in perl

[dawood munavar]

I have the size of a text file (say 1MB) and i have the location to save the text file (say C:/) , how do i create a file in perl which should be 1MB size and which should save in C:/. Give me some suggestions or ideas. Your help will be appreciated.

[RonB]

See: `perldoc -f sysopen`
and: `perldoc -f syswrite`

[dawood munavar]

perldoc -f sysopen: Is it a code for creating a file or i need to search on this code..

[RonB]

sysopen and syswrite are Perl functions for opening and writing to files.

perldoc is a command that you run from the command line to access the Perl documentation.

You can also access the documentation online.
http://perldoc.perl.org/functions/sysopen.html
http://perldoc.perl.org/functions/syswrite.html

[dawood munavar]

thanku so much RonB!!!! you are wonderfull...

[dawood munavar]

#!/usr/bin/perl
 
use Fcntl;
 
print "enter the SIZE of a file \n";
$file=<STDIN>;
 
print "enter the location of a file \n";
$loc= <STDIN>;
chomp($loc);
 
sysopen( FILEIN, $loc ,O_CREAT|O_WRONLY);
print FILEIN "hai how r u \n";
close(FILEIN);
 

#In this perl program, im getting the size(1Mb) and location of a file( C:\) from the user. when compiling this
program, the file is saved properly under the location user wants ( C:\) but How to
create a file with the size(1mb) user wants??

[RonB]

Use syswrite instead of print.

Please read the documentation that I pointed you to, it will show how how to specify the size.

[dawood munavar]

#!/usr/bin/perl
 
use Fcntl;
 
print "enter the SIZE of a file \n";
$file=<STDIN>;
chomp($file);
 
print "enter the location of a file \n";
$loc= <STDIN>;
chomp($loc);
 
$new= "hai how are you \n";
 
sysopen( FILEIN, $loc ,O_CREAT|O_WRONLY);
syswrite( FILEIN, $new, $file);
close(FILEIN);
 

#When i compile this program, say im giving the size as 4096, the file is saved properly
under the location it wants but the file size is not equal to user's input. Could you please
tell me what is the error??

[RonB]

Currently the size of the file will be the length of the string in $new.

You need add another print statement which adds enough characters to bring the size up to the desired level.

[dawood munavar]

no its not working!!! could you please tell me clearly

[RonB]

use strict;
use warnings;
use Fcntl;
 
my $size = 1024;
my $str = 'some random text';
$str .= ' ' x ( $size - length($str) );
 
sysopen( my $fh, 'test.txt' , O_CREAT|O_WRONLY);
syswrite $fh, $str;
 

[dawood munavar]

#!/usr/bin/perl
 
use Fcntl;
 
$new= "hai how are you \n";
 
print "enter the SIZE of a file in BYTES\n";
$file=<STDIN>;
chomp($file);
 
print "enter the location of a file \n";
$loc= <STDIN>;
chomp($loc);
 
$new .= ' ' x ( $file- length($new));
 
sysopen( FILEIN, $loc , O_CREAT|O_WRONLY);
syswrite( FILEIN, $new);
close(FILEIN);
 

#This perl program is working perfectly. RonB, you are amazing.
But last question, could you please explain,

$new .= ' ' x ( $file- length($new));
 

what this line does??