fix and add comments to test.sh

test.sh

@@ -1,21 +1,29 @@
 #!/bin/bash
-set -u 
-set -e 
+set -u
+set -e
 
+# generate 1Mbit of random data
 dd if=/dev/urandom of=data.send bs=125kB count=1 status=none
-./send.py tx.int16 < data.send
 
+# modulate data into audio file
+./send.py <data.send >tx.int16
+
+# stop old recording and start a new one
 killall -q arecord aplay || true
-
 ./wave.py record rx.int16 &
-sleep 1
+sleep 1  # let rx.int16 be filled
 
-./recv.py rx.int16 > data.recv &
-./wave.py play   tx.int16 
+# start the receiever
+./recv.py <rx.int16 >data.recv &
 
+# play the modulated data
+./wave.py play   tx.int16
+
+# stop recording after playing is over
 killall -q arecord aplay || true
 
-./errors.py data.* 
+# verify transmittion
+./errors.py data.*
 sha256sum data.* | ./colorhash.py
 if [ -z $? ]; then
 	./show.py tx.int16 rx.int16