Go - Flag (Argument Parsing)
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The Flag package to parse Go arguments passed to entry point of the application (main)
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How to
Change the usage (adding an header, footer)
To change the usage output, you need to overwrite the Usage variable.
Example to add an header and a footer
flag.Usage = func() {
fmt.Fprintln(os.Stderr, "An header")
fmt.Fprintf(os.Stderr, "Usage of %s:\n", os.Args[0])
flag.PrintDefaults()
fmt.Fprintln(os.Stderr, "A footer")
}
Get the arguments without flag (the last arguments)
The non-flag arguments are available from flag.Args()
fmt.Println("tail:", flag.Args())