And -Dr displays compiled regular expressions; the format of the output is explained in perldebguts. In particular, both CRLF translation and intuiting ":utf8" from the locale are disabled.
In this documentation, "! You perhaps were thinking of ":crlf:bytes" or ":perlio:bytes". Precede any character that needs to be protected, like a space or backslash, with another backslash.
See "Deferred Signals Safe Signals " in perlipc. If Perl is installed, you receive a message indicating its version. The capital -E instead of -e tells perl that you intend to use say and other 5.
See "Location of Perl". If that can't be done, system administrators are strongly encouraged to put symlinks to perl and its accompanying utilities into a directory typically found along a user's PATH, or in some other obvious and convenient place.
Contained in the file specified by the first filename on the command line. The versions are similar, so it's entirely up to you. Do not disclose the hash seed to people who don't need to know it.