rename expect script to use proper file extension; fix other things as needed

tester/run-xv6-command.exp

@@ -0,0 +1,43 @@
+#! /usr/bin/env expect
+
+proc shutdown {} {
+    # send command to halt qemu (ctrl-a x)
+    # https://stackoverflow.com/questions/27050473/how-to-send-ctrl-a-then-d-in-expect
+    send "\x01"; send "x"
+    # make sure to wait for it all to stop
+    # (without this, script was terminating before qemu quit -> bad)
+    expect eof
+}
+
+# turn off timeout (perhaps make this flexible later)
+set timeout -1
+
+# build and launch xv6 on qemu
+spawn make [lindex $argv 0] -f [lindex $argv 1] qemu-nox
+
+trap {
+    shutdown
+    exit 0
+} SIGINT
+
+# wait for initial prompt
+expect "init: starting sh\r"
+expect "$ "
+
+# send command as per command line
+send "[lindex $argv 2]\r"
+
+# wait for it to be done
+expect "$ "
+
+# shutdown qemu properly (avoid runaways)
+shutdown
+
+
+
+
+
+
+
+
+