@make.sh command -v has > /dev/null. set -x

  `$GXX ...` `set +x`, outputs such as
```
~/SubStack $ ./make.sh
/* Dual licenses: choose "Creative Commons" or "Apache 2" (allows all uses) */
+ clang++ -fsanitize=address -fno-sanitize-recover=all -fsanitize=float-divide-by-zero -fsanitize=float-cast-overflow -fno-sanitize=null -fno-sanitize=alignment -fno-omit-frame-pointer -g -x c -c ./cxx//../c/rfc6234/sha1.c
+ clang++ -fsanitize=address -fno-sanitize-recover=all -fsanitize=float-divide-by-zero -fsanitize=float-cast-overflow -fno-sanitize=null -fno-sanitize=alignment -fno-omit-frame-pointer -g -x c -c ./cxx//../c/rfc6234/sha224-256.c
+ clang++ -fsanitize=address -fno-sanitize-recover=all -fsanitize=float-divide-by-zero -fsanitize=float-cast-overflow -fno-sanitize=null -fno-sanitize=alignment -fno-omit-frame-pointer -g -x c -c ./cxx//../c/rfc6234/sha384-512.c
+ clang++ -fsanitize=address -fno-sanitize-recover=all -fsanitize=float-divide-by-zero -fsanitize=float-cast-overflow -fno-sanitize=null -fno-sanitize=alignment -fno-omit-frame-pointer -g -c ./cxx//ClassSha2.cxx
+ clang++ -fsanitize=address -fno-sanitize-recover=all -fsanitize=float-divide-by-zero -fsanitize=float-cast-overflow -fno-sanitize=null -fno-sanitize=alignment -fno-omit-frame-pointer -g -c ./cxx//ClassResultList.cxx
+ clang++ -fsanitize=address -fno-sanitize-recover=all -fsanitize=float-divide-by-zero -fsanitize=float-cast-overflow -fno-sanitize=null -fno-sanitize=alignment -fno-omit-frame-pointer -g -c ./cxx//ClassCns.cxx
+ clang++ -fsanitize=address -fno-sanitize-recover=all -fsanitize=float-divide-by-zero -fsanitize=float-cast-overflow -fno-sanitize=null -fno-sanitize=alignment -fno-omit-frame-pointer -g -c ./cxx//VirusAnalysis.cxx
+ clang++ -fsanitize=address -fno-sanitize-recover=all -fsanitize=float-divide-by-zero -fsanitize=float-cast-overflow -fno-sanitize=null -fno-sanitize=alignment -fno-omit-frame-pointer -g -c ./cxx//ConversationCns.cxx
./cxx//ConversationCns.cxx:106:74: warning: non-void function does not return a value [-Wreturn-type]
  106 | const FileBytecode conversationParseQuestion(const FilePath &xhtmlFile) {} /* TODO */
      |                                                                          ^
./cxx//ConversationCns.cxx:107:88: warning: non-void function does not return a value [-Wreturn-type]
  107 | const std::vector<FileBytecode> conversationParseResponses(const FilePath &xhtmlFile) {} /* TODO */
      |                                                                                        ^
2 warnings generated.
+ clang++ -fsanitize=address -fno-sanitize-recover=all -fsanitize=float-divide-by-zero -fsanitize=float-cast-overflow -fno-sanitize=null -fno-sanitize=alignment -fno-omit-frame-pointer -g -c ./cxx//main.cxx
+ clang++ -fsanitize=address -fno-sanitize-recover=all -fsanitize=float-divide-by-zero -fsanitize=float-cast-overflow -fno-sanitize=null -fno-sanitize=alignment -fno-omit-frame-pointer -g sha1.o sha224-256.o sha384-512.o ClassSha2.o ClassResultList.o ClassCns.o VirusAnalysis.o ConversationCns.o main.o
+ set +x
~/SubStack $

make.sh

@@ -10,12 +10,12 @@ CXX_FLAGS_DEBUG="${CXX_FLAGS_DEBUG} -fno-omit-frame-pointer" #/* thus optimizati
 CXX_FLAGS_DEBUG="${CXX_FLAGS_DEBUG} -g" #/* gives line numbers, + arguments, to stacktraces */
 #CXX_FLAGS_DEBUG="${CXX_FLAGS_DEBUG} -fno-optimize-sibling-calls" #/* Don't inline functions. Does extra stacktraces. */
 #CXX_FLAGS_DEBUG="${CXX_FLAGS_DEBUG} -fsanitize=undefined" #/* causes 'cannot locate symbol "__ubsan_handle_function_type_mismatch_abort"' */
-if command -v ctags; then
+if command -v ctags > /dev/null; then
 	ctags -R
 fi
-if command -v clang++; then
+if command -v clang++ > /dev/null; then
 	CXX="clang++"
-elif command -v g++; then
+elif command -v g++ > /dev/mull; then
 	CXX="g++"
 else
 	echo "Error: no clang++, no g++. `apt install clang` or `apt install gcc`"
@@ -24,6 +24,7 @@ fi
 rm *.o
 CXX_FLAGS="${CXX_FLAGS} ${CXX_FLAGS_DEBUG}" #/* comment this to disable sanitizers/stacktraces (if you want to run fast) */
 CXX="${CXX} ${CXX_FLAGS}"
+set -x
 $CXX -x c -c ${sSRC}/../c/rfc6234/sha1.c
 $CXX -x c -c ${sSRC}/../c/rfc6234/sha224-256.c
 $CXX -x c -c ${sSRC}/../c/rfc6234/sha384-512.c
@@ -34,4 +35,5 @@ $CXX -c ${sSRC}/VirusAnalysis.cxx
 $CXX -c ${sSRC}/ConversationCns.cxx
 $CXX -c ${sSRC}/main.cxx
 $CXX sha1.o sha224-256.o sha384-512.o ClassSha2.o ClassResultList.o ClassCns.o VirusAnalysis.o ConversationCns.o main.o
+set +x