add loop-rebuild script

diff --git a/loop-rebuild b/loop-rebuild
new file mode 100755 (executable)
index 0000000..c2b94a1
--- /dev/null
+++ b/loop-rebuild
@@ -0,0 +1,25 @@
+#!/bin/sh
+
+ssleep () {
+       seconds=$1
+       now=$(date "+%s")
+       sleep $(( ((now + seconds + seconds / 4) / seconds) * seconds - now))
+}
+
+stamp () {
+       Meta/V 2>/dev/null | sha1sum
+}
+
+P=previous
+O=observed
+while :
+do
+       while O=$(stamp) && test "$P" = "$O"
+       do
+               ssleep 300
+       done
+       ssleep 30
+       time nice -20 Meta/Dothem -j16 --scratch --dash; uptime; date
+       P=$(stamp)
+       Meta/V
+done