added --docker option to run the same clang-format than container on CI

do-clang-format.py

@@ -69,9 +69,9 @@ else:
         filelist_clean.append(f)
     filelist = filelist_clean
 
-cmd = ["clang-format"]
+cmd = "clang-format"
 if "CLANG_FORMAT" in os.environ:
-  cmd = [os.environ["CLANG_FORMAT"]]
+  cmd = os.environ["CLANG_FORMAT"]
 if args.docker: 
   USER=os.environ["USER"]
   UID=os.getuid()
@@ -80,10 +80,14 @@ if args.docker:
   # note, currently in container it is clang-8 
   cmd = "docker container run --rm -v {}:/corsika -w /corsika -u {}:{} corsika/devel:clang-8 clang-format-8".format(PWD,UID,GID)
 cmd += " -style=file"
+
+version = subp.check_output(cmd.split() + ["--version"]).decode("utf-8")
+print (version)
+
 if args.apply:
     for filename in filelist:        
         subp.check_call(cmd.split() + ["-i", filename])
-
+        
 else:
     # only print files which need formatting
     files_need_formatting = 0