add cmd check

.hooks/pre-commit

@@ -14,7 +14,8 @@ changed_files=$(git diff-index --cached $against | \
 	grep -E '[MA]	.*\.(c|cpp|cc|cxx)$' | cut -d'	' -f 2)
 
 
-if [ -n "$changed_files" ]; then
+if which cppcheck > /dev/null; then 
+	if [ -n "$changed_files" ]; then
 		cppcheck --enable=warning,performance,portability --inline-suppr --error-exitcode=1 --platform=win64 --force $changed_files
 		err=$?
 		if [ $err -ne 0 ]; then
@@ -23,6 +24,9 @@ if [ -n "$changed_files" ]; then
 		else
 			echo "[rt-thread][cppcheck] cppcheck ok."
 		fi
+	fi
+else
+    echo "cppcheck does not exist" 
 fi
 
 # We only filter the file name with c or cpp or h file.
@@ -30,8 +34,8 @@ fi
 changed_files=$(git diff-index --cached $against | \
 	grep -E '[MA]	.*\.(c|cpp|h)$' | cut -d'	' -f 2)
 
-
-if [ -n "$changed_files" ]; then
+if which astyle > /dev/null; then 
+	if [ -n "$changed_files" ]; then
 		astyle --style=allman --indent=spaces=4 --indent=spaces=4 --indent=spaces=4 --pad-header --pad-header --pad-header --align-pointer=name --lineend=linux --convert-tabs --verbose  $changed_files
 		err=$?
 		if [ $err -ne 0 ]; then
@@ -40,20 +44,27 @@ if [ -n "$changed_files" ]; then
 		else
 			echo "[rt-thread][astyle] astyle file ok"
 		fi
+	fi
+else
+    echo "astyle does not exist" 
 fi
 
-
 # We only filter the file name with c or cpp file.
 changed_files=$(git diff-index --cached $against | \
 	grep -E '[MA]	.*\.(c|cpp|h)$' | cut -d'	' -f 2)
 # formatting check
 # https://github.com/mysterywolf/formatting
 # formatting cmd ref https://github.com/supperthomas/git_auto_script
-if [ -n "$changed_files" ]; then
+if which formatting > /dev/null; then 
+	if [ -n "$changed_files" ]; then
 		formatting $changed_files
 		echo "[rt-thread] formatting $changed_files is ok"
 		git add $changed_files
 		exit 0
+	fi
+else
+    echo "formatting does not exist" 
 fi
+
 exit 0