fix: Better error messages for kitsch init.

cmd/init.go

@@ -3,16 +3,24 @@ package cmd
 import (
 	"fmt"
 	"os"
+	"strings"
 
 	"github.com/jwalton/kitsch/internal/kitsch/initscripts"
+	"github.com/jwalton/kitsch/internal/kitsch/log"
 	"github.com/spf13/cobra"
 )
 
 var initCmd = &cobra.Command{
-	Use:   "init",
+	Use:   "init [shell]",
 	Short: "Returns a script which can be used to initialize " + programName + ".",
-	Args:  cobra.ExactArgs(1),
 	Run: func(cmd *cobra.Command, args []string) {
+		if len(args) != 1 {
+			_ = cmd.Usage()
+			validShells := strings.Join(initscripts.ValidShells(), ", ")
+			log.Error("init command requires the name of a shells.  Use one of: " + validShells + ".")
+			os.Exit(1)
+		}
+
 		shell := args[0]
 
 		printFullInit, err := cmd.Flags().GetBool("print-full-init")

internal/kitsch/initscripts/init.go

@@ -5,6 +5,7 @@ import (
 	"embed"
 	"fmt"
 	"os"
+	"strings"
 	"text/template"
 )
 
@@ -46,7 +47,8 @@ func getInitScript(filename string, shell string, configFile string) (string, er
 
 	initTemplate, err := initTemplates.ReadFile("templates/" + shell + "-" + filename + "." + shellExt)
 	if err != nil {
-		return "", fmt.Errorf("invalid shell %s", shell)
+		validShells := strings.Join(ValidShells(), ", ")
+		return "", fmt.Errorf("invalid shell %s.  Use one of: %s", shell, validShells)
 	}
 
 	return execTemplate(string(initTemplate), data)

internal/kitsch/initscripts/setup.go

@@ -18,6 +18,15 @@ var shellConfigFiles = map[string]string{
 	"powershell": "Microsoft.PowerShell_profile.ps1 (you can find the location of this file by running `echo $PROFILE`)",
 }
 
+// ValidShells returns a list of valid shell types.
+func ValidShells() []string {
+	result := []string{}
+	for supportedShell := range shellConfigFiles {
+		result = append(result, supportedShell)
+	}
+	return result
+}
+
 // ShowSetupInstructions prints setup instructions for the given shell.
 func ShowSetupInstructions(
 	programName string,