Japhy already answered your question, but I thought I'd add that when you write this:

if (/^-+\$boundary/){
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It means to match a literal $ sign, then the string 'boundary.' To do what you want, just do what japhy said and use:

if (/^-+\Q$boundary\E/){
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(or you can use quotemeta on $boundary)

The 15 year old, freshman programmer,
Stephen Rawls