Unittest - Document the magic line in wrapper.sh

test/test_hooks/wrapper.sh

@@ -8,7 +8,9 @@ OUT="${ORIGINALHOOK}.log.out"
 # Let it know that we were executed
 echo "% Called at $(date +%s%N)" >> ${IN}
 
+# Log what arrives via stdin to ${IN} and what comes via stdout to ${OUT}
 $ORIGINALHOOK < <(tee -a ${IN}) > >(tee -a ${OUT})
+# More on the < <() syntax at: http://tldp.org/LDP/abs/html/process-sub.html
 
 EXITCODE=$?
 echo "! Exit code: ${EXITCODE}" >> ${OUT}