Further improve 2000/schneiderwent/try.sh

Now allows one to override how long to sleep and how many iterations to
go through. It is an error if non positive values are specified.

2000/schneiderwent/README.md

@@ -28,6 +28,15 @@ paint dry :-) ) you might also try:
 ./try.sh
 ```
 
+Alternatively, you can check on it later on, to see all the entry does. Or if
+you wish to make it run faster, you can override how long it sleeps per
+iterations and how many iterations it runs. For instance to make it sleep only
+30 seconds and run only twice:
+
+```sh
+SLEEP=30 ITERATIONS=2 ./try.sh
+```
+
 
 ## Judges' remarks:
 

2000/schneiderwent/try.sh

@@ -6,23 +6,50 @@
 # make sure CC is set so that when we do make CC="$CC" it isn't empty. Doing it
 # this way allows us to have the user specify a different compiler in an easy
 # way.
-if [[ -z "$CC" ]]; then
-    CC="cc"
-fi
+[[ -z "$CC" ]] && CC="cc"
 
 make CC="$CC" all >/dev/null || exit 1
 
 # clear screen after compilation so that only the entry is shown
 clear
 
-echo "This will take a long time to run to completion: " 1>&2
+# get the number of seconds to sleep in between runs (def: 60)
+[[ -z "$SLEEP" ]] && SLEEP=60
+# verify it's a positive number:
+echo "$SLEEP" | grep -qE '^[0-9]+'
+if [[ "${PIPESTATUS[1]}" -ne 0 ]]; then
+    echo "SLEEP value not a positive number, fix and run again."
+    exit 1
+fi
+# get the number of iterations to run (default: 60)
+[[ -z "$ITERATIONS" ]] && ITERATIONS=60
+# verify it's a positive number:
+echo "$ITERATIONS" | grep -qE '^[0-9]+'
+if [[ "${PIPESTATUS[1]}" -ne 0 ]]; then
+    echo "ITERATIONS value not a positive number, fix and run again."
+    exit 1
+fi
+
+echo "If you did not override \$SLEEP and \$ITERATIONS this will take a long" 1>&2
+echo "time to run to completion: approximately one hour. If you do not care to" 1>&2
+echo "wait such a long time, which we presume is probably quite likely, you" 1>&2
+echo "you might wish to run this entry like the following: " 1>&2
+echo 1>&2
+echo "    ./schneiderwent" 1>&2
+echo "    ./schneiderwent schneiderwent.data" 1>&2
+echo 1>&2
+echo "at various times throughout the day, preferably at different" 1>&2
+echo "minutes of the hours." 1>&2
+echo 1>&2
+echo "Alternatively, you can leave this running in a console tab for an hour" 1>&2
+echo "and look back at it later, so that you can see all the entry does." 1>&2
+echo 1>&2
+read -r -n 1 -p "Press any key to start: "
+echo 1>&2
 i=0
-while [[ "$i" -lt 60 ]]; do
+while [[ "$i" -lt "$ITERATIONS" ]]; do
     ./schneiderwent
     ./schneiderwent schneiderwent.data
-    sleep 60
+    sleep "$SLEEP"
     ((i++))
 done
-
-
-