ishell

ishell is an interactive shell library for creating interactive cli applications.

Older version

The current master is not backward compatible with older version. Kindly change your import path to gopkg.in/abiosoft/ishell.v1.

Older version of this library is still available at https://gopkg.in/abiosoft/ishell.v1.

However, you are advised to upgrade.

Usage

import "strings"
import "github.com/abiosoft/ishell"

func main(){
    // create new shell.
    // by default, new shell includes 'exit', 'help' and 'clear' commands.
    shell := ishell.New()

    // display welcome info.
    shell.Println("Sample Interactive Shell")

    // register a function for "greet" command.
    shell.AddCmd(&ishell.Cmd{
        Name: "greet",
        Help: "greet user",
        Func: func(c *ishell.Context) {
            c.Println("Hello", strings.Join(c.Args, " "))
        },
    })

    // run shell
    shell.Run()
}

Execution

Sample Interactive Shell
>>> help

Commands:
  clear      clear the screen
  greet      greet user
  exit       exit the program
  help       display help

>>> greet Someone Somewhere
Hello Someone Somewhere
>>> exit
$

Reading input.

// simulate an authentication
shell.AddCmd(&ishell.Cmd{
    Name: "login",
    Help: "simulate a login",
    Func: func(c *ishell.Context) {
        // disable the '>>>' for cleaner same line input.
        c.ShowPrompt(false)
        defer c.ShowPrompt(true) // yes, revert after login.

        // get username
        c.Print("Username: ")
        username := c.ReadLine()

        // get password.
        c.Print("Password: ")
        password := c.ReadPassword()

        ... // do something with username and password

        c.Println("Authentication Successful.")
    },
})

Execution

>>> login
Username: someusername
Password:
Authentication Successful.

Multiline input.

Builtin support for multiple lines.

>>> This is \
... multi line

>>> Cool that << EOF
... everything here goes
... as a single argument.
... EOF

User defined

shell.AddCmd(&ishell.Cmd{
    Name: "multi",
    Help: "input in multiple lines",
    Func: func(c *ishell.Context) {
        c.Println("Input multiple lines and end with semicolon ';'.")
        lines := c.ReadMultiLines(";")
        c.Println("Done reading. You wrote:")
        c.Println(lines)
    },
})

Execution

>>> multi
Input multiple lines and end with semicolon ';'.
>>> this is user defined
... multiline input;
You wrote:
this is user defined
multiline input;

Keyboard interrupt.

Builtin interrupt handler.

>>> ^C
Input Ctrl-C once more to exit
>>> ^C
Interrupted
exit status 1

Custom

shell.Interrupt(func(count int, c *ishell.Context) { ... })

Multiple Choice

func(c *ishell.Context) {
    choice := c.MultiChoice([]string{
        "Golangers",
        "Go programmers",
        "Gophers",
        "Goers",
    }, "What are Go programmers called ?")
    if choice == 2 {
        c.Println("You got it!")
    } else {
        c.Println("Sorry, you're wrong.")
    }
},

Output

What are Go programmers called ?
  Golangers
  Go programmers
❯ Gophers
  Goers

You got it!

Checklist

func(c *ishell.Context) {
    languages := []string{"Python", "Go", "Haskell", "Rust"}
    choices := c.Checklist(languages,
        "What are your favourite programming languages ?", nil)
    out := func() []string { ... } // convert index to language 
    c.Println("Your choices are", strings.Join(out(), ", "))
}

Output

What are your favourite programming languages ?
    Python
  ✓ Go
    Haskell
 ❯✓ Rust

Your choices are Go, Rust

Progress Bar

Determinate

func(c *ishell.Context) {
    c.ProgressBar().Start()
    for i := 0; i < 101; i++ {
        c.ProgressBar().Suffix(fmt.Sprint(" ", i, "%"))
        c.ProgressBar().Progress(i)
        ... // some background computation
    }
    c.ProgressBar().Stop()
}

Output

[==========>         ] 50%

Indeterminate

func(c *ishell.Context) {
    c.ProgressBar().Indeterminate(true)
    c.ProgressBar().Start()
    ... // some background computation
    c.ProgressBar().Stop()
}

Output

[ ====               ]

Custom display using briandowns/spinner.

display := ishell.ProgressDisplayCharSet(spinner.CharSets[11])
func(c *Context) { c.ProgressBar().Display(display) ... }

// or set it globally
ishell.ProgressBar().Display(display)

Durable history.

// Read and write history to $HOME/.ishell_history
shell.SetHomeHistoryPath(".ishell_history")

Non-interactive execution

In some situations it is desired to exit the program directly after executing a single command.

// when started with "exit" as first argument, assume non-interactive execution
if len(os.Args) > 1 && os.Args[1] == "exit" {
    shell.Process(os.Args[2:]...)
} else {
    // start shell
    shell.Run()
}

# Run normally - interactive mode:
$ go run main.go
>>> |

# Run non-interactivelly
$ go run main.go exit greet Someusername
Hello Someusername

Example

Available here.

go run example/main.go

Supported Platforms

• Linux
• OSX
• Windows [Not tested but should work]

Note

ishell is in active development and can still change significantly.

Roadmap (in no particular order)

• Multiline inputs.
• Command history.
• Customizable tab completion.
• Handle ^C interrupts.
• Subcommands and help texts.
• Scrollable paged output.
• Progress bar.
• Multiple choice prompt.
• Checklist prompt.
• Multiple line progress bars.
• Testing, testing, testing.

Contribution

1. Create an issue to discuss it.
2. Send in Pull Request.

License

MIT

Credits

Library	Use
github.com/flynn-archive/go-shlex	splitting input into command and args.
github.com/chzyer/readline	readline capabilities.

Donate

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