Some pointers:

• use strict; it helps!
• `perldoc -q 'quoting.*vars'` (!)
• $lupd is nonsense
• @nupd is nonsense
• $lline is nonsense if you match case-insensitive , see perlop
• And perlre knows your mistake. '$line =~ /x86\.exe/'
• Always, (really always), check the return value of open()! Check close() when you have written to a file.

HTH

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