subroutine and deleting a line in a file

hello... i am working hard again trying to learn perl...

i have a script that inputs data into a file line by line... if i want to change one of those lines... the script will do that...

i have two questions...

#1 how do i delete a line...?

i have tried: undef $line (actually it reads as: undef $changes[$fields{linenumber}];

this undefines the line, but leaves me with a blank line or a n still in the file, so my output is all messed up...

i don't know how to "erase" the line completely...

#2 how do i call a subroutine using a variable...?

i have two submit buttons... "adjust" and
"delete"... when the adjust button is pushed i want to call the subroutine:

&adjust;

when the delete button is pushed:

&delete;

my variables are parsed in the form of:

$fields{key}... so i tried to call the sub by using:

&$fields{key};

this did not work... all i got was a server error...

how do i call a sub using a variable like this...?

here is that portion of the script:


######################################
# subroutine delete file
######################################

sub Delete
{

$out="cgi-bin/order/$ENV{'REMOTE_ADDR'}.txt";

open OUT, "$out" or die "Cannot open $out for write :$!";

read(OUT,$oldstuff,10000);

close OUT;

@changes=split(/n/,$oldstuff);

open OUT, ">$out" or die "Cannot open $out for write :$!";

undef $changes[$fields{linenumber}]; ### this leaves a blank line which messes up my output ###


for $x (0 .. $#changes)

{
print OUT "$changes[$x]n";
}

close OUT;

}

######################################
# subroutine adjust file
######################################

sub Adjust
{

$out="cgi-bin/order/$ENV{'REMOTE_ADDR'}.txt";

open OUT, "$out" or die "Cannot open $out for write :$!";

read(OUT,$oldstuff,10000);

close OUT;

@changes=split(/n/,$oldstuff);

open OUT, ">$out" or die "Cannot open $out for write :$!";

$changes[$fields{linenumber}]=$adjust;

for $x (0 .. $#changes)

{
print OUT "$changes[$x]n";
}

close OUT;

}

Have you read my example at all? http://www.devshed.com/Talk/Forums/Forum6/HTML/000166.html

>>#1 how do i delete a line...?
Remove the following will DELETE instead of ADJUST:
open(OUT,">>$out");
flock (OUT, 2);
print OUT "$FORM{'num'}|$FORM{'ip'}n";
close(OUT);

>> have two submit buttons... "adjust" and
"delete"...
On your html form, assign field name to each of the two submit buttons..
<input type=submit name=adjust value=Adjust>
<input type=submit name=delete value=Delete>

Look back to my previous example, the 'Parse Form' could be something like..

read(STDIN, $buffer, $ENV{'CONTENT_LENGTH'});
@pairs = split(/&/, $buffer);
foreach $pair (@pairs) {
($name, $value) = split(/=/, $pair);
$value =~ tr/+/ /;
$value =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C", hex($1))/eg;
$value =~ s/<!--(.|n)*-->//g;
$value =~ s/<([^>]|n)*>//g;
$value =~ s/^s+//;
$value =~ s/s+$//;
$FORM{$name} = $value;
}
# next, determine action type
if ($FORM{'delete}) {
&delete;
elsif ($FORM{'adjust'}) {
&adjust;
}
else {
print "Unable to determine action typen";
}