Support setting target directory in hugo gen man

Fixes #1627

commands/genman.go

@@ -2,12 +2,15 @@ package commands
 
 import (
 	"fmt"
+	"strings"
 
 	"github.com/spf13/cobra"
 	"github.com/spf13/hugo/helpers"
+	"github.com/spf13/hugo/hugofs"
 	jww "github.com/spf13/jwalterweatherman"
 )
 
+var genmandir string
 var genmanCmd = &cobra.Command{
 	Use:   "man",
 	Short: "Generate man pages for the Hugo CLI",
@@ -16,15 +19,27 @@ command-line interface.  By default, it creates the man page files
 in the "man" directory under the current directory.`,
 
 	Run: func(cmd *cobra.Command, args []string) {
-		genmandir := "man/"
-		cmd.Root().DisableAutoGenTag = true
 		header := &cobra.GenManHeader{
 			Section: "1",
 			Manual:  "Hugo Manual",
 			Source:  fmt.Sprintf("Hugo %s", helpers.HugoVersion()),
 		}
+		if !strings.HasSuffix(genmandir, helpers.FilePathSeparator) {
+			genmandir += helpers.FilePathSeparator
+		}
+		if found, _ := helpers.Exists(genmandir, hugofs.OsFs); !found {
+			jww.FEEDBACK.Println("Directory", genmandir, "does not exist, creating...")
+			hugofs.OsFs.MkdirAll(genmandir, 0777)
+		}
+		cmd.Root().DisableAutoGenTag = true
+
 		jww.FEEDBACK.Println("Generating Hugo man pages in", genmandir, "...")
 		cmd.Root().GenManTree(header, genmandir)
+
 		jww.FEEDBACK.Println("Done.")
 	},
 }
+
+func init() {
+	genmanCmd.PersistentFlags().StringVar(&genmandir, "dir", "man/", "the directory to write the man pages.")
+}