echo on

reg export HKLM\Software\Classes\.pl saved.reg /y
reg delete HKLM\Software\Classes\.pl /f

assoc .pl=perltest
perl -e"system(qq(ftype perltest=$^X \"%%1\" %%*))"
ftype perltest

mkdir pipe
cd pipe
pipe

perl -e "print 'print qq(| $_) while <>'" > pipe.pl
set pathext=.pl;.com;.exe;.bat;.cmd;
pipe pipe.pl
pipe < pipe.pl
type pipe.pl | pipe

set pathext=.com;.exe;.bat;.cmd;
pipe pipe.pl
pipe < pipe.pl

set pathext=.com;.exe;.bat;.cmd;.pl;
pipe pipe.pl
pipe < pipe.pl
type pipe.pl | pipe

del pipe.pl
cd ..
rmdir pipe

reg delete HKLM\Software\Classes\.pl /f
reg import saved.reg
del saved.reg