cli is a library for implementing powerful command-line interfaces in Go. cli is the library that powers the CLI for Packer, Serf, Consul, Vault, Terraform, and Nomad.
Features
-
Easy sub-command based CLIs:
cli foo
,cli bar
, etc. -
Support for nested subcommands such as
cli foo bar
. -
Optional support for default subcommands so
cli
does something other than error. -
Support for shell autocompletion of subcommands, flags, and arguments with callbacks in Go. You don't need to write any shell code.
-
Automatic help generation for listing subcommands
-
Automatic help flag recognition of
-h
,--help
, etc. -
Automatic version flag recognition of
-v
,--version
. -
Helpers for interacting with the terminal, such as outputting information, asking for input, etc. These are optional, you can always interact with the terminal however you choose.
-
Use of Go interfaces/types makes augmenting various parts of the library a piece of cake.
Example
Below is a simple example of creating and running a CLI
package main
import (
"log"
"os"
"github.com/mitchellh/cli"
)
func main() {
c := cli.NewCLI("app", "1.0.0")
c.Args = os.Args[1:]
c.Commands = map[string]cli.CommandFactory{
"foo": fooCommandFactory,
"bar": barCommandFactory,
}
exitStatus, err := c.Run()
if err != nil {
log.Println(err)
}
os.Exit(exitStatus)
}