How to display usage information for a Go program with defined flags?

To display usage information for a Go program with defined flags, you can use the flag package in Go. Here's an example of how you can do it:

Import the flag package:

import "flag"

Define the flags for your program:

var (
    flag1 = flag.String("flag1", "default value", "description for flag1")
    flag2 = flag.Int("flag2", 0, "description for flag2")
    // ... define more flags
)

Create a function to print the usage information:

func printUsage() {
    flag.PrintDefaults()
}

Parse the command-line arguments:

flag.Parse()

Optionally, you can check if the user has provided the -h or --help flag to print the usage information and exit the program:

if len(os.Args) > 1 && (os.Args[1] == "-h" || os.Args[1] == "--help") {
    printUsage()
    os.Exit(0)
}

Now, when you run your program with the -h or --help flag, it will display the usage information, including the defined flags and their descriptions.

For example:

$ go run main.go -h
Usage of /tmp/go-build1415292925/b001/exe/main:
  -flag1 string
        description for flag1 (default "default value")
  -flag2 int
        description for flag2 (default 0)
  ...

Note: Make sure to replace main.go with the actual name of your Go file.