When referring to the language, the name is normally capitalized ("Perl") as a proper noun. When referring to the interpreter program itself, the name is often uncapitalized ("perl") because most Unix-like file systems are case-sensitive. Before the release of the first edition of "Programming Perl", it was common to refer to the language as "perl"; Randal L. Schwartz, however, capitalized the language's name in the book to make it stand out better when typeset. This case distinction was subsequently documented as canonical.