I have the following yasnippets defined in my emacs.

$ cat ~/.emacs.d/snippets/cperl-mode/slurp
# -*- snippet -*-
#key: slurp
#group: slurp
#name: Slurp file-handle
# --
my $${1:variable} = do { local $/; <$${2:fh}>; };
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$ cat ~/.emacs.d/snippets/cperl-mode/slurp.open
# -*- snippet -*-
#key: slurp
#group: slurp
#name: Open and slurp
# --
my $${1:variable} = do {$>
local $/;$>
open( my $${2:fh}, q{<}, ${3:$WHAT} )$>
  or die qq{Can't open "$3": $!\n};
<$$2>;$>
};$>
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