shellcheck fixes in 2020/kurdyukov2

try.sh now runs makegif.sh.

Fix makegif.sh to first compile the program, allow one to specify CC and
convert and check that the output file was created. In the case
convert(1) is not found or it fails to generate the output file it
suggests the user look at the FAQ entry about ImageMagick.

2020/kurdyukov2/README.md

@@ -19,6 +19,7 @@ make
 ./prog 1000 selfie.jpg output.jpg
 # Admire your portrait in cubist style
 
+# Also try:
 ./try.sh
 ```
 
@@ -98,7 +99,7 @@ After that’s installed you need to run make with these options:
 make LDFLAGS="-I/opt/local/include -L/opt/local/lib"
 ```
 
-### Building on macOS with HomeBrew
+### Building on macOS with Homebrew
 
 First, make sure you have the compiler tools installed e.g. by:
 
@@ -106,7 +107,7 @@ First, make sure you have the compiler tools installed e.g. by:
 sudo xcode-select --install
 ```
 
-Make sure you install [HomeBrew](https://brew.sh).
+Make sure you install [Homebrew](https://brew.sh).
 
 Then:
 
@@ -139,9 +140,11 @@ You can use this command to make a GIF from output images (uses ImageMagick).
 For instance after running the command suggested by the judges:
 
 ```sh
-convert -delay 10 -dither none -loop 0 $(ls out*.jpg | sort -V) $(ls out*.jpg | sort -rV) +map out.gif
+convert -delay 10 -dither none -loop 0 $(find . -maxdepth 1 -type f -name '*jpg' | sort -V) $(find . -maxdepth 1 -type f -name '*jpg' | sort -rV) +map out.gif
 ```
 
+NOTE: the above is done in the [try.sh](try.sh) script.
+
 Also provided `makegif.sh` to aid with GIF creation.