lncli+makefile: generate man pages automatically for lncli and lnd

Makefile

@@ -3,6 +3,8 @@ ESCPKG := github.com\/lightningnetwork\/lnd
 MOBILE_PKG := $(PKG)/mobile
 TOOLS_DIR := tools
 
+PREFIX ?= /usr/local
+
 BTCD_PKG := github.com/btcsuite/btcd
 GOACC_PKG := github.com/ory/go-acc
 GOIMPORTS_PKG := github.com/rinchsan/gosimports/cmd/gosimports
@@ -122,12 +124,20 @@ build-itest-race:
 	@$(call print, "Building itest binary for ${backend} backend.")
 	CGO_ENABLED=0 $(GOTEST) -v ./itest -tags="$(DEV_TAGS) $(RPC_TAGS) integration $(backend)" -c -o itest/itest.test$(EXEC_SUFFIX)
 
-#? install: Build and install lnd and lncli binaries, place them in $GOPATH/bin
-install:
+#? install-binaries: Build and install lnd and lncli binaries, place them in $GOPATH/bin
+install-binaries:
 	@$(call print, "Installing lnd and lncli.")
 	$(GOINSTALL) -tags="${tags}" -ldflags="$(RELEASE_LDFLAGS)" $(PKG)/cmd/lnd
 	$(GOINSTALL) -tags="${tags}" -ldflags="$(RELEASE_LDFLAGS)" $(PKG)/cmd/lncli
 
+#? manpages: generate and install man pages
+manpages:
+	@$(call print, "Generating man pages lncli.1 and lnd.1.")
+	./scripts/gen_man_pages.sh $(DESTDIR) $(PREFIX)
+
+#? install: Build and install lnd and lncli binaries, place them in $GOPATH/bin, generate and install man pages
+install: install-binaries manpages
+
 #? release-install: Build and install lnd and lncli release binaries, place them in $GOPATH/bin
 release-install:
 	@$(call print, "Installing release lnd and lncli.")

cmd/lncli/commands.go

@@ -18,6 +18,8 @@ import (
 
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/wire"
+	"github.com/jessevdk/go-flags"
+	"github.com/lightningnetwork/lnd"
 	"github.com/lightningnetwork/lnd/lnrpc"
 	"github.com/lightningnetwork/lnd/routing"
 	"github.com/lightningnetwork/lnd/routing/route"
@@ -1410,6 +1412,41 @@ func channelBalance(ctx *cli.Context) error {
 	return nil
 }
 
+var generateManPageCommand = cli.Command{
+	Name: "generatemanpage",
+	Usage: "Generates a man page for lncli and lnd as " +
+		"lncli.1 and lnd.1 respectively.",
+	Hidden: true,
+	Action: actionDecorator(generateManPage),
+}
+
+func generateManPage(ctx *cli.Context) error {
+	// Generate the man pages for lncli as lncli.1.
+	manpages, err := ctx.App.ToMan()
+	if err != nil {
+		return err
+	}
+	err = os.WriteFile("lncli.1", []byte(manpages), 0644)
+	if err != nil {
+		return err
+	}
+
+	// Generate the man pages for lnd as lnd.1.
+	config := lnd.DefaultConfig()
+	fileParser := flags.NewParser(&config, flags.Default)
+	fileParser.Name = "lnd"
+
+	var buf bytes.Buffer
+	fileParser.WriteManPage(&buf)
+
+	err = os.WriteFile("lnd.1", buf.Bytes(), 0644)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
 var getInfoCommand = cli.Command{
 	Name:   "getinfo",
 	Usage:  "Returns basic information related to the active daemon.",

cmd/lncli/main.go

@@ -508,6 +508,7 @@ func main() {
 		fishCompletionCommand,
 		listAliasesCommand,
 		estimateRouteFeeCommand,
+		generateManPageCommand,
 	}
 
 	// Add any extra commands determined by build flags.