#!/usr/bin/perl: No such file or directory
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The shell reports the whole shebang line as a non-existent file? Something's wrong with that line. What's there before the shebang? Is there by chance a <Ctrl>H or such? Delete that line and write it again.

Then,

#!/usr/bin/perl -w
use 5.18.2;
#use strict;
#use warnings;
#use utf8;
say "Hello";
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you should not comment out use strict; and use warnings; until your program runs and you are dead sure it does what it is meant to do with no ways left to fail.