C:\test>set PATHEXT=.COM;.EXE;.BAT;.CMD;

C:\test>junk.pl junk.pl
'print "'$_'" while <>;
'
C:\test>junk junk.pl

C:\test>set PATHEXT=.pl;.COM;.EXE;.BAT;.CMD;

C:\test>junk junk.pl
'print "'$_'" while <>;
'