G'day MP,

Net::SSH::Perl->new( $host, [identity_files => [$keyfile]);
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It's best to copy-paste code rather than type it manually; I'm assuming that's what you did and introduced a typo.

$ perl -MO=Deparse -e 'Net::SSH::Perl->new( $host, [identity_files => 
+[$keyfile]);'
syntax error at -e line 1, near "])"
Missing right curly or square bracket at -e line 1, at end of line
-e had compilation errors.
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So, perhaps your real code has (completely guessing):

Net::SSH::Perl->new( $host, [identity_files => [$keyfile]]);
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Regardless, if you look at the Net::SSH::Perl doco, you'll see

Net::SSH::Perl->new($host, %params)
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And, further down in the description of %params: "identity_files ... a reference to an array of strings ...". There's more information there, which you should read, but it would seem that you really want:

Net::SSH::Perl->new($host, identity_files => [$keyfile]);
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