Thanks ikegami. But I still don't understand why I get the error from a script containing the same logic of another, the only difference is that variable being the defaulted $_ while the other is user-defined Eg: my $r Below are the scripts I tested... I'd like to assign a string or even a large body of text to a variable other than $_ Can you help? Thanks.

my $r = "Time to work";
s/work/play/;
print $r;
#end of script 1

#script 2
$_ = "Time to work";
s/work/play/;
print $_
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the only difference is that variable being the defaulted $_ while the other is user-defined

Nope, no "user-defined" variables being used by s/// in either snippet.

my $r = "Time to work";
s/work/play/;
print $r;
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means

my $r = "Time to work";
$_ =~ s/work/play/;
print $r;
[download]

Since you never assigned anything to $_, you get a warning. Conversely, you never told s/// to work on $r. Doing either will solve the problem.

my $_ = "Time to work";
s/work/play/;
print $_;
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my $r = "Time to work";
$r =~ s/work/play/;
print $r;
[download]

Thanks very much again ikegami.