added few tests

README.md

@@ -5,9 +5,28 @@ A utility to scan for TLS certificates in a network segment in CIDR format to qu
 
 This is written in GO and the assets are currently only build for Linux amd64.  
 
-The concurrency for host cert checking is currently set to 128.
+The concurrency for host cert checking is currently set to 128, tested 1024 which is faster.
 
 ## Usage
+
+### Command Flags
+```
+Usage information:
+  -cidr string
+    	network cidr list (default "192.168.10.0/24,192.168.11.0/24")
+  -conc int
+    	concurrent connections (default 128)
+  -html string
+    	html output file
+  -json string
+    	json output file
+  -ports string
+    	tcp port list (default "443,636,587,8443")
+  -skipnodns
+    	skip no dns found
+  -v	version
+```
+
 ### Linux amd64
 ```
 #single subnet, single port, output to console only
@@ -21,6 +40,9 @@ The concurrency for host cert checking is currently set to 128.
 
 #multiple subnets, multiple ports, output to console only
 ./certchecker_linux -cidr=10.10.10.0/24,10.10.20.0/24 -ports=443,8443
+
+#multiple subnets, multiple ports, output to console only, 1024 concurrent checks
+./certchecker_linux -cidr=10.10.10.0/24,10.10.20.0/24 -ports=443,8443 -conc=1024
 ```
 ## Output
 ### Console

internal/output/output.go

@@ -73,7 +73,7 @@ func CreateOutFile(data []certs.TlsCert, fileName string, templateFile string, A
 		fmt.Printf("error execute template: %v\n", err)
 		return
 	}
-
+	fmt.Printf("Output file created: %s\n", fileName)
 }
 
 // JsonMeta holds the metadata
@@ -99,7 +99,12 @@ func CreateJsonFile(data []certs.TlsCert, fileName string) {
 		fmt.Println("error parsing data to json: ", err)
 		return
 	}
-	f.Write(jsonData)
+	_, err = f.Write(jsonData)
+	if err != nil {
+		fmt.Println("error writing data to file: ", err)
+		return
+	}
+	fmt.Printf("Output file created: %s\n", fileName)
 }
 
 // exp formats the expired status

main.go

@@ -17,13 +17,19 @@ var buildTime string
 
 func main() {
 
+	flag.Usage = func() {
+		fmt.Fprintf(flag.CommandLine.Output(), "Cert Checker git-sha1:%v buildtime:%v\n", sha1ver, buildTime)
+		fmt.Fprintf(flag.CommandLine.Output(), "Usage information:\n")
+		flag.PrintDefaults()
+	}
+
 	cidrAddressList := flag.String("cidr", "192.168.10.0/24,192.168.11.0/24", "network cidr list")
 	portList := flag.String("ports", "443,636,587,8443", "tcp port list")
 	skipNoDnsFound := flag.Bool("skipnodns", false, "skip no dns found")
 	htmlOut := flag.String("html", "", "html output file")
 	jsonOut := flag.String("json", "", "json output file")
 	concurrent := flag.Int("conc", 128, "concurrent connections")
-	ver := flag.Bool("v", false, fmt.Sprintf("version (sha:%s buildtime:%s)", sha1ver, buildTime))
+	ver := flag.Bool("v", false, "version")
 	flag.Parse()
 	if *ver {
 		fmt.Printf("version: %s\n", sha1ver)