Add version option to display app version

Makefile

@@ -4,8 +4,8 @@ all: bin/purl
 go.mod go.sum:
 	go mod tidy
 
-bin/purl: main.go cli/*.go
-	go build -o bin/purl main.go
+bin/purl: main.go cli/*.go go.mod go.sum
+	go build -ldflags "-X github.com/catatsuy/purl/cli.Version=`git rev-list HEAD -n1`" -o bin/purl main.go
 
 .PHONY: vet
 vet:

README.md

@@ -16,6 +16,7 @@ Purl is a versatile text processing tool designed to easily and efficiently modi
 - **`-replace`**: This option requires a replacement expression to specify the text you intend to change. Format your command as "@search@replace@", with "search" being the text to find and "replace" the text to insert.
 - **`-color`** and **`-no-color`**: By default, Purl's output colorization is set to auto, determining the best mode based on your environment. Use `-no-color` if you prefer the output without colorization, regardless of the environment.
 - **`-help`**: Display information about Purl and its various options.
+- **`-version`**: Display version.
 
 ## Usage Examples
 

cli/cli.go

@@ -7,6 +7,8 @@ import (
 	"io"
 	"os"
 	"regexp"
+	"runtime"
+	"runtime/debug"
 
 	"golang.org/x/term"
 )
@@ -17,6 +19,22 @@ const (
 	ExitCodeFail           = 1
 )
 
+var (
+	Version string
+)
+
+func version() string {
+	if Version != "" {
+		return Version
+	}
+
+	info, ok := debug.ReadBuildInfo()
+	if !ok {
+		return "(devel)"
+	}
+	return info.Main.Version
+}
+
 type rawStrings []string
 
 func (i *rawStrings) String() string {
@@ -39,10 +57,13 @@ type CLI struct {
 	excludes    rawStrings
 	help        bool
 	color       bool
+	version     bool
+
+	appVersion string
 }
 
 func NewCLI(outStream, errStream io.Writer, inputStream io.Reader) *CLI {
-	return &CLI{outStream: outStream, errStream: errStream, inputStream: inputStream}
+	return &CLI{appVersion: version(), outStream: outStream, errStream: errStream, inputStream: inputStream}
 }
 
 func (c *CLI) Run(args []string) int {
@@ -52,6 +73,11 @@ func (c *CLI) Run(args []string) int {
 		return ExitCodeParseFlagError
 	}
 
+	if c.version {
+		fmt.Fprintf(c.errStream, "purl version %s; %s\n", c.appVersion, runtime.Version())
+		return ExitCodeOK
+	}
+
 	if c.help {
 		flags.Usage()
 		return ExitCodeOK
@@ -150,9 +176,10 @@ func (c *CLI) parseFlags(args []string) (*flag.FlagSet, error) {
 	flags.BoolVar(&c.color, "color", false, "Colored output. Default auto.")
 	flags.BoolVar(&noColor, "no-color", false, "Disable colored output.")
 	flags.BoolVar(&c.help, "help", false, `Show help`)
+	flags.BoolVar(&c.version, "version", false, "Print version and quit")
 
 	flags.Usage = func() {
-		fmt.Fprintln(c.errStream, "Usage: purl [options] [file]")
+		fmt.Fprintf(c.errStream, "purl version %s; %s\nUsage: purl [options] [file]\n", c.appVersion, runtime.Version())
 		flags.PrintDefaults()
 	}
 

cli/cli_test.go

@@ -81,6 +81,11 @@ func TestRun_success(t *testing.T) {
 			args:         []string{"purl", "-help"},
 			expectedCode: 0,
 		},
+		{
+			desc:         "version option",
+			args:         []string{"purl", "-version"},
+			expectedCode: 0,
+		},
 		{
 			desc:         "filter",
 			args:         []string{"purl", "-filter", "search"},