File handling? How to make the better one?

[heatblazer]

Hello again!

I`ve actually managed to crete my serverside perl script for creating and/or overwriting an existing json file for my JSONP script. But my perl script is kinda weird. I had to open file 2 times, truncate it and the process looks not reliable... or it`s ok...

I need a quick review and an info if the script is good to go or it must undergo some maintenance.

#!/opt/lampp/bin/perl
use strict;
use CGI;

#####    S    U    B    S    #########
sub speaker {
    my $text = shift;
    print  "Content-type: text/html\n\n";
    print $text;
}

sub makeJSON {
    #create and record a JSON file 
    my ( $name, $mail, $pass ) = @_;
    if ( system("ls -l | grep datafile.json") == 0 ) {
        my $replace_me =""; #the storage for replace;
        my $jobj = "\n \t\t{ \"name\":\t\"$name\",\n\t\t\"mail\":\t\"$
+mail\",\n\t\t\"pass\":\t\"$pass\",\n\t\t },\n];";
        open (FH, "</opt/lampp/htdocs/datafile.json") or die("can`t op
+en filehandle: $!\n");
        while ( <FH> ) {
            if ( /\]/ ) {
                $replace_me .= $jobj;
            }
            else {
                $replace_me .= $_;
            }
        }
        close(FH);
        #truncate and create again
        open (FR, ">/opt/lampp/htdocs/datafile.json") or die("can`t op
+en filehandle: $!\n");
        print FR $replace_me;
        close(FR);
    }
    else {
        
        my $jobj = "var user = [ \n\t\t{ \"name\":\t\"$name\",\n\t\t\"
+mail\":\t\"$mail\",\n\t\t\"pass\":\t\"$pass\",\n\t\t },\n];";
        open (FH, ">/opt/lampp/htdocs/datafile.json") or die("can`t op
+en filehandle: $!\n");
        print FH $jobj;
        close(FH);
    }
        
        print "Content-type: text/html\n\n";
        print "<p>Finished file</p>";
    
}


##################################################
my $q = CGI->new();
my ($name, $mail, $pass) = (
                            $q->param('name'),
                            $q->param('mail'),
                            $q->param('pass'),
                        );
makeJSON($name, $mail, $pass);

THanks in advance