Improve usage and update readme

README.md

@@ -16,11 +16,23 @@ go install github.com/bcongdon/ep
 ## Usage
 
 ```
-ep
+Usage of ./ep:
+./ep [QUERY]
+  -noninteractive
+    	If set, doesn't display emoji picker -- instead just outputting the first selection for the provided query.
+  -output string
+    	The output of ep. Choices: clipboard, stdout (default "clipboard")
 ```
 
 Navigation can be done with the arrow keys. Pressing `Enter` copies the selected emoji to the clipboard.
 
+### Examples
+
+- `ep` - Opens the default emoji picker.
+- `ep wink` - Opens the default emoji picker with the query "wink" already entered
+- `ep -noninteractive wink` - Copies the first search result for "wink" to the clipboard
+- `ep -noninteractive -output=stdout wink` - Outputs the first search result for "wink" to stdout
+
 ## Troubleshooting
 
 - If you see blank squares in the emoji grid, these emojis cannot be rendered by your terminal's font.

main.go

@@ -6,6 +6,7 @@ import (
 	"flag"
 	"fmt"
 	"log"
+	"os"
 	"sort"
 	"strings"
 
@@ -20,6 +21,12 @@ const numCols int = 10
 var outputFlag = flag.String("output", "clipboard", "The output of ep. Choices: clipboard, stdout")
 var noninteractiveFlag = flag.Bool("noninteractive", false, "If set, doesn't display emoji picker -- instead just outputting the first selection for the provided query.")
 
+var usageFunc = func() {
+	fmt.Fprintf(flag.CommandLine.Output(), "Usage of %s:\n", os.Args[0])
+	fmt.Fprintf(flag.CommandLine.Output(), "%s [QUERY]\n", os.Args[0])
+	flag.PrintDefaults()
+}
+
 type Emoji struct {
 	Keywords []string `json:"keywords"`
 	Char     string   `json:"char"`
@@ -107,6 +114,7 @@ func runNoninterativeMode(emojis map[string][]Emoji, query string) {
 }
 
 func main() {
+	flag.Usage = usageFunc
 	flag.Parse()
 	validateFlags()