Fix 2020/kurdyukov2 make clobber, .gitignore, try

2020/kurdyukov2/.gitignore

@@ -1,6 +1,9 @@
 #
 # sort with: sort -d -u
 *.dSYM
+*.jpg
+*.gif
+*.ppm
 indent
 indent.c
 indent.o

2020/kurdyukov2/Makefile

@@ -212,7 +212,7 @@ clean:
 
 clobber: clean
 	${RM} -f ${TARGET} ${ALT_TARGET}
-	${RM} -rf *.dSYM
+	${RM} -rf *.dSYM *.gif *.ppm out*.jpg
 	@-if [ -e sandwich ]; then \
 	    ${RM} -f sandwich; \
 	    echo 'ate sandwich'; \

2020/kurdyukov2/try.sh

@@ -6,18 +6,26 @@
 # 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 "$CC" || ! -f "$CC" || ! -x "$CC" ]] && CC="cc"
 
 make CC="$CC" all >/dev/null || exit 1
 
 # clear screen after compilation so that only the entry is shown
 clear
 
-# try finding convert(1) from ImageMagick
-CONVERT="$(type -P convert)"
+# try finding convert(1) from ImageMagick if CONVERT not passed to script or is
+# not an executable file
+[[ -z "$CONVERT" || ! -f "$CONVERT" || ! -x "$CONVERT" ]] && CONVERT="$(type -P convert)"
 
+convert_error()
+{
+    echo 1>&2
+    echo "Warning: $CONVERT failed to generate out.gif. Is $CONVERT convert(1) from ImageMagick?" 1>&2
+    echo "See: https://github.com/ioccc-src/temp-test-ioccc/blob/master/faq.md#imagemagick." 1>&2
+    echo 1>&2
+    echo "Tip: if you have it in a different path, try: CONVERT=path ./try.sh" 1>&2
+    echo 1>&2
+}
 
 echo "$ (echo P6 1024 1024 255; dd if=/dev/urandom bs=3M count=1) > random.ppm" 1>&2
 (echo P6 1024 1024 255; dd if=/dev/urandom bs=3M count=1) > random.ppm
@@ -25,10 +33,10 @@ echo "Look at random.ppm. Do you see any patterns?" 1>&2
 read -r -n 1 -p "Press any key to continue: "
 echo 1>&2
 # Look at random.ppm. Do you see any patterns?
-echo "$ ./prog_ppm 1000 random.ppm output.ppm" 1>&2
+read -r -n 1 -p "Press any key to run: ./prog_ppm 1000 random.ppm output.ppm: "
+echo 1>&2
 ./prog_ppm 1000 random.ppm output.ppm
 echo 1>&2
-# See which patterns the program has found
 echo "Now open output.ppm. What patterns has the program found?" 1>&2
 echo 1>&2
 read -r -n 1 -p "Press any key to continue: "
@@ -36,7 +44,10 @@ echo 1>&2
 
 echo "$ for i in 0001 0002 0004 0008 0016 0032 0064 0128
   0256 0512 1024 2048 4096 8192 ; do ./prog $i sample.jpg out$i.jpg; done" 1>&2
-for i in 0001 0002 0004 0008 0016 0032 0064 0128 0256 0512 1024 2048 4096 8192 ; do ./prog "$i" sample.jpg "out$i".jpg; done
+for i in 0001 0002 0004 0008 0016 0032 0064 0128 0256 0512 1024 2048 4096 8192 ; do
+    read -r -n 1 -p "Press any key to run: ./prog $i sample.jpg out$i.jpg: "
+    echo 1>&2
+    ./prog "$i" sample.jpg "out$i".jpg; done
 echo "Now flip through out*.jpg and see when you start to recognise the image." 1>&2
 
 if [[ -n "$CONVERT" ]]; then
@@ -45,7 +56,16 @@ if [[ -n "$CONVERT" ]]; then
     echo 1>&2
     echo "$ $CONVERT -delay 10 -dither none -loop 0 $(ls out*.jpg | sort -V) $(ls out*.jpg | sort -rV) +map out.gif" 1>&2
     "$CONVERT" -delay 10 -dither none -loop 0 $(ls out*.jpg | sort -V) $(ls out*.jpg | sort -rV) +map out.gif
+    if [[ ! -f out.gif ]]; then
+	convert_error
+    else
+	echo 1>&2
+	echo "Now look at out.gif with a graphics viewer that can show animated GIFs." 1>&2
+	echo "Warning: includes flashing colours." 1>&2
+    fi
+else
+    echo 1>&2
+    echo "Could not fine convert(1) from ImageMagick." 1>&2
+    echo "See: https://github.com/ioccc-src/temp-test-ioccc/blob/master/faq.md#imagemagick." 1>&2
     echo 1>&2
-    echo "Now look at out.gif with a viewer that can show animation." 1>&2
-    echo "Warning: includes flashing colours." 1>&2
 fi