Rewrite help to match httpie added capabilities

README.md

@@ -25,5 +25,4 @@ See [HTTPie doc](https://httpie.org/doc) for more examples.
 ## Differences with httpie
 
 * Like `curl` but unlike `httpie`, headers are written on `stderr` instead of `stdout`.
-* Output is not buffered, all the formatting is done on the fly so you can easily debug streamed data.
-* 
+* Output is not buffered, all the formatting is done on the fly so you can easily debug streamed data.

formatter/help.go

@@ -0,0 +1,22 @@
+package formatter
+
+import (
+	"bytes"
+	"io"
+)
+
+type HelpAdapter struct {
+	Out     io.Writer
+	CmdName string
+}
+
+func (j HelpAdapter) Write(p []byte) (n int, err error) {
+	cmd := "http"
+	if len(j.CmdName) == 0 {
+		cmd = j.CmdName
+	}
+	p = bytes.Replace(p,
+		[]byte("curl [options...] <url>"),
+		[]byte(cmd+" [options...] [METHOD] URL [REQUEST_ITEM [REQUEST_ITEM ...]]"), 1)
+	return j.Out.Write(p)
+}

main.go

@@ -22,8 +22,13 @@ func main() {
 	verbose := opts.Has("verbose") || opts.Has("v")
 	quiet := opts.Has("silent") || opts.Has("s")
 
-	// Remove progress bar.
-	opts = append(opts, "-sS")
+	if len(opts) == 0 {
+		// Show help if no args
+		opts = append(opts, "-h")
+	} else {
+		// Remove progress bar.
+		opts = append(opts, "-sS")
+	}
 
 	// Change default method based on binary name.
 	switch os.Args[0] {
@@ -33,41 +38,44 @@ func main() {
 		}
 	}
 
-	if data := opts.Val("d"); data != "" {
-		// If data is provided via -d, read it from there for the verbose mode.
-		// XXX handle the @filename case.
-		w := &formatter.JSON{
-			Out:    input,
-			Scheme: formatter.DefaultColorScheme,
-		}
-		w.Write([]byte(data))
-	} else if !terminal.IsTerminal(0) {
-		// If something is piped in to the command, tell curl to use it as input.
-		opts = append(opts, "-d@-")
-		// Tee the stdin to the buffer used show the posted data in verbose mode.
-		stdin = io.TeeReader(stdin, &formatter.JSON{
-			Out:    input,
-			Scheme: formatter.DefaultColorScheme,
-		})
-	}
-	if terminal.IsTerminal(1) {
-		// Format/colorize JSON output if stdout is to the terminal.
-		stdout = &formatter.JSON{
-			Out:    stdout,
-			Scheme: formatter.DefaultColorScheme,
+	if opts.Has("h") || opts.Has("help") {
+		stdout = &formatter.HelpAdapter{Out: stdout, CmdName: os.Args[0]}
+	} else {
+		if data := opts.Val("d"); data != "" {
+			// If data is provided via -d, read it from there for the verbose mode.
+			// XXX handle the @filename case.
+			w := &formatter.JSON{
+				Out:    input,
+				Scheme: formatter.DefaultColorScheme,
+			}
+			w.Write([]byte(data))
+		} else if !terminal.IsTerminal(0) {
+			// If something is piped in to the command, tell curl to use it as input.
+			opts = append(opts, "-d@-")
+			// Tee the stdin to the buffer used show the posted data in verbose mode.
+			stdin = io.TeeReader(stdin, &formatter.JSON{
+				Out:    input,
+				Scheme: formatter.DefaultColorScheme,
+			})
 		}
-	}
-	if terminal.IsTerminal(2) {
-		// If stderr is not redirected, output headers.
-		if !quiet {
-			opts = append(opts, "-v")
+		if terminal.IsTerminal(1) {
+			// Format/colorize JSON output if stdout is to the terminal.
+			stdout = &formatter.JSON{
+				Out:    stdout,
+				Scheme: formatter.DefaultColorScheme,
+			}
 		}
-		stderr = &formatter.HeaderColorizer{
-			Out:    stderr,
-			Scheme: formatter.DefaultColorScheme,
+		if terminal.IsTerminal(2) {
+			// If stderr is not redirected, output headers.
+			if !quiet {
+				opts = append(opts, "-v")
+			}
+			stderr = &formatter.HeaderColorizer{
+				Out:    stderr,
+				Scheme: formatter.DefaultColorScheme,
+			}
 		}
 	}
-	fmt.Println(opts)
 	cmd := exec.Command("curl", opts...)
 	cmd.Stdin = stdin
 	cmd.Stdout = stdout