Renamed 'cmd' to 'kg' so that go install works correctly

kg/main.go

@@ -61,6 +61,11 @@ func main() {
 		panic("Invalid match number to print.")
 	}
 
+	// Enable lineFlag if lineNumFlag is enabled
+	if *lineNumFlag {
+		*lineFlag = true
+	}
+
 	// Process:
 	// 1. Convert regex into postfix notation (Shunting-Yard algorithm)
 	// 		a. Add explicit concatenation operators to facilitate this
@@ -68,11 +73,11 @@ func main() {
 	// 3. Run the string against the NFA
 
 	if len(flag.Args()) < 1 { // flag.Args() also strips out program name
-		fmt.Println("ERROR: Missing cmdline args")
+		fmt.Printf("%s: ERROR: Missing cmdline args\n", os.Args[0])
 		os.Exit(22)
 	}
 	if *recursiveFlag && len(flag.Args()) < 2 { // File/Directory must be provided with '-r'
-		fmt.Println("ERROR: Missing cmdline args")
+		fmt.Printf("%s: ERROR: Missing cmdline args\n", os.Args[0])
 		os.Exit(22)
 	}
 	var re string
@@ -87,12 +92,22 @@ func main() {
 		for _, inputFilename := range inputFilenames {
 			inputFile, err := os.Open(inputFilename)
 			if err != nil {
-				fmt.Printf("%s: No such file or directory\n", flag.Args()[1])
+				fmt.Printf("%s: %s: No such file or directory\n", os.Args[0], inputFilename)
+			} else {
+				fileStat, err := inputFile.Stat()
+				if err != nil {
+					fmt.Printf("%v\n", err)
 					os.Exit(2)
-			}
+				} else {
+					if fileStat.Mode().IsDir() {
+						fmt.Printf("%s: %s: Is a directory\n", os.Args[0], inputFilename)
+					} else {
 						inputFiles = append(inputFiles, inputFile)
 					}
 				}
+			}
+		}
+	}
 
 	var test_str string
 	var err error
@@ -108,6 +123,7 @@ func main() {
 	}
 
 	for _, inputFile := range inputFiles {
+		lineNum = 0
 		reader := bufio.NewReader(inputFile)
 		linesRead = false
 		for true {
@@ -202,8 +218,13 @@ func main() {
 				if !(*invertFlag) && len(matchIndices) == 0 || *invertFlag && len(matchIndices) > 0 {
 					continue
 				} else {
+					if *recursiveFlag || len(flag.Args()) > 2 { // If we have 2 args, then we're only searching 1 file. We should only print the filename if there's more than 1 file.
 						color.New(color.FgMagenta).Fprintf(out, "%s:", inputFile.Name()) // Print filename
 					}
+					if *lineNumFlag {
+						color.New(color.FgGreen).Fprintf(out, "%d:", lineNum) // Print filename
+					}
+				}
 			}
 
 			// If we are substituting, we need a different behavior, as follows:

regex/compile.go

@@ -47,6 +47,7 @@ func (re *Reg) UnmarshalText(text []byte) error {
 	return err
 }
 
+// Longest makes future searches prefer the longest branch of an alternation, as opposed to the leftmost branch.
 func (re *Reg) Longest() {
 	re.preferLongest = true
 }