php code:
<? print shell_exec("tclsh8.4 user.tcl username password");
?>

tcl code (user.tcl):
#to check if the php print multi lines
puts test1\n
puts test2\n
#to check if the $::argv works
puts [lrange $::argv 0 end]\n
#open a file
set fileopen111 [open path/to/file r]
#print anything again
puts "the end\n"