Minor cleanup, mostly...

bin/processing-commander

@@ -1,8 +1,16 @@
 #!/bin/bash
+set -e
+
 TOP="$(dirname $(dirname $(readlink -f -- "$0")))"
 
+$TOP/bin/prochome-check >/dev/null
+
+if [ ! -f "$TOP/lib/preferences.txt" ]; then
+    cp "$TOP/lib/preferences.txt.stub" "$TOP/lib/preferences.txt"
+fi
+
 CP="$CLASSPATH"
-CP="$TOP/lib/$(uname -a)/mbh-processing-practice.jar:$CP"
+CP="$TOP/lib/$(uname -m)/mbh-processing-practice.jar:$CP"
 for procjar in "lib/core" "lib/pde" "java/lib/tools" "java/lib/rt"
 do
     CP="$PROCESSING_HOME/$procjar.jar:$CP"