add upgrade command

cmd/upgrade.go

@@ -0,0 +1,39 @@
+package cmd
+
+import (
+	"fmt"
+	"os/exec"
+	"regexp"
+
+	"github.com/bootdotdev/bootdev/version"
+	"github.com/spf13/cobra"
+)
+
+var upgradeCmd = &cobra.Command{
+	Use:     "upgrade",
+	Aliases: []string{"update"},
+	Short:   "Installs the latest version of the CLI.",
+	Run: func(cmd *cobra.Command, args []string) {
+		info := version.FromContext(cmd.Context())
+		if !info.IsOutdated {
+			fmt.Println("Boot.dev CLI is already up to date.")
+			return
+		}
+		// install the latest version
+		command := exec.Command("go", "install", "github.com/bootdotdev/bootdev@latest")
+		b, err := command.Output()
+		cobra.CheckErr(err)
+
+		// Get the new version info
+		command = exec.Command("bootdev", "--version")
+		b, err = command.Output()
+		cobra.CheckErr(err)
+		re := regexp.MustCompile(`v\d+\.\d+\.\d+`)
+		version := re.FindString(string(b))
+		fmt.Printf("Successfully upgraded to %s!\n", version)
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(upgradeCmd)
+}

version.txt

@@ -1 +1 @@
-v1.6.0
+v1.6.1

version/version.go

@@ -42,7 +42,7 @@ func (v *VersionInfo) PromptUpdateIfAvailable() {
 	if v.IsOutdated {
 		fmt.Fprintln(os.Stderr, "A new version of the bootdev CLI is available!")
 		fmt.Fprintln(os.Stderr, "Please run the following command to update:")
-		fmt.Fprintf(os.Stderr, "  go install github.com/%s/%s@latest\n\n", repoOwner, repoName)
+		fmt.Fprintf(os.Stderr, "  bootdev upgrade\n\n")
 	}
 }