c:\test>set pathext
PATHEXT=.pl;.pl8;.com;.exe;.bat;.cmd;

c:\test>assoc .pl
.pl=Perl

c:\test>ftype perl
perl="C:\Perl64\bin\perl.exe" "%1" %*

c:\test>assoc .pl8
.pl8=perl8

c:\test>ftype perl8
perl8="C:\perl32\bin\perl.exe" "%1" %*