feat: add flag to print version

cmd/yamlfmt/flags.go

@@ -28,6 +28,7 @@ source yaml and formatted yaml.`)
 	flagDry *bool = flag.Bool("dry", false, `Perform a dry run; show the output of a formatting
 operation without performing it.`)
 	flagIn              *bool   = flag.Bool("in", false, "Format yaml read from stdin and output to stdout")
+	flagVersion         *bool   = flag.Bool("version", false, "Print yamlfmt version")
 	flagConf            *string = flag.String("conf", "", "Read yamlfmt config from this path")
 	flagDoublestar      *bool   = flag.Bool("dstar", false, "Use doublestar globs for include and exclude")
 	flagQuiet           *bool   = flag.Bool("quiet", false, "Print minimal output to stdout")

cmd/yamlfmt/main.go

@@ -16,13 +16,16 @@ package main
 
 import (
 	"flag"
+	"fmt"
 	"log"
 
 	"github.com/google/yamlfmt"
 	"github.com/google/yamlfmt/command"
 	"github.com/google/yamlfmt/formatters/basic"
 )
 
+var version string = "0.10.0"
+
 func main() {
 	if err := run(); err != nil {
 		log.Fatal(err)
@@ -34,6 +37,11 @@ func run() error {
 	configureHelp()
 	flag.Parse()
 
+	if *flagVersion {
+		fmt.Printf("%s\n", version)
+		return nil
+	}
+
 	c := &command.Command{
 		Operation: getOperationFromFlag(),
 		Registry:  getFullRegistry(),

docs/command-usage.md

@@ -59,13 +59,14 @@ All flags must be specified **before** any path arguments.
 
 These flags adjust the command's mode of operation. All of these flags are booleans.
 
-| Name       | Flag     | Example                    | Description |
-|:-----------|:---------|:---------------------------|:------------|
-| Help       | `-help`  | `yamlfmt -help`            | Print the command usage information. |
-| Dry Run    | `-dry`   | `yamlfmt -dry .`           | Use [Dry Run](#dry-run) mode |
-| Lint       | `-lint`  | `yamlfmt -lint .`          | Use [Lint](#lint) mode |
-| Quiet Mode | `-quiet` | `yamlfmt -dry -quiet .`    | Use quiet mode. Only has effect in Dry Run or Lint modes. |
-| Read Stdin | `-in`    | `cat x.yaml | yamlfmt -in` | Read input from stdin and output result to stdout. |
+| Name          | Flag       | Example                     | Description                                               |
+| :------------ | :--------- | :-------------------------- | :-------------------------------------------------------- |
+| Help          | `-help`    | `yamlfmt -help`             | Print the command usage information.                      |
+| Print Version | `-version` | `yamlfmt -version`          | Print the yamlfmt version.                                |
+| Dry Run       | `-dry`     | `yamlfmt -dry .`            | Use [Dry Run](#dry-run) mode                              |
+| Lint          | `-lint`    | `yamlfmt -lint .`           | Use [Lint](#lint) mode                                    |
+| Quiet Mode    | `-quiet`   | `yamlfmt -dry -quiet .`     | Use quiet mode. Only has effect in Dry Run or Lint modes. |
+| Read Stdin    | `-in`      | `cat x.yaml \| yamlfmt -in` | Read input from stdin and output result to stdout.        |
 
 ### Configuration Flags