Flag.Parse
flag.Parse is a Go flag-package function that parses command-line arguments according to defined flags and assigns their values to registered variables.
Learn Go with Pocket-Sized Projects
flag.Parse is a Go flag-package function that parses command-line arguments and stores the resulting values in registered flag variables.
- How it is used
- Parses explicit command-line flags for small Go programs and command-line interfaces.
- How deep it goes
- Explains registration, call ordering, destination variables, defaults, pointers, and positional arguments, stopping short of parser internals.
- Examples
- Uses a language-selectable greeting and a currency converter with source, target, and positional amount inputs.
- What you can do after
- Operate/configure Go command-line programs by registering flags, parsing input, reading values, and validating required data.
Read how Learn Go with Pocket-Sized Projects explains flag.Parse →
Go in Practice, Second Edition
flag.Parse is a Go flag-package function that parses the defined command-line flags and assigns their values.
- How it is used
- Parses command-line flags after registration so a Go CLI can use user-provided values.
- How deep it goes
- Explains placement, invalid-input exits, declaration-order overwrites, and type validation, while deferring alternatives to later treatment.
- Examples
- Uses a Hello World CLI with name, Spanish, shorthand, invalid, and repeated Boolean arguments.
- What you can do after
- Operate/configure a Go CLI by registering flags, parsing arguments, and handling built-in validation behavior.
Read how Go in Practice, Second Edition explains flag.Parse →
Related concepts
- flag packagepart of · The flag package is Go’s standard-library package for defining, parsing, retrieving, and documenting command-line flags.
- command-line argumentuses · A command-line argument is a value supplied to a program when it is invoked, either as positional input or as an option that configures its behavior.
These guides are generated from the text of Manning books by Manning's knowledge graph and link to the sections they draw on. The full books are available on liveBook and at manning.com.