in reply to Altering the value of "$/"
From the perlman:perlvar page
The values of '' and undef both have pre-defined meanings in the context of the $/ variable.Works like awk's RS variable, including treating empty lines as delimiters if set to the null string. ... You may set it to a multi-character string to match a multi-character delimiter, or to undef to read to end of file.
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Seekers of Perl Wisdom