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readline

Readline is A Pure Go Implementation of a libreadline-style Library.
The goal is to be a powerful alternater for GNU-Readline.

WHY: Readline will support most of features which GNU Readline is supported, and provide a pure go environment and a MIT license.

Demo

Also works fine in windows

You can read the source code in example/main.go.

Todo

Vim mode
More funny examples

Usage

Simplest example

import "github.com/chzyer/readline"

rl, err := readline.New("> ")
if err != nil {
	panic(err)
}
defer rl.Close()

for {
	line, err := rl.Readline()
	if err != nil { // io.EOF
		break
	}
	println(line)
}

Example with durable history

rl, err := readline.NewEx(&readline.Config{
	Prompt: "> ",
	HistoryFile: "/tmp/readline.tmp",
})
if err != nil {
	panic(err)
}
defer rl.Close()

for {
	line, err := rl.Readline()
	if err != nil { // io.EOF
		break
	}
	println(line)
}

Example with auto refresh

import (
	"log"
	"github.com/chzyer/readline"
)

rl, err := readline.New("> ")
if err != nil {
	panic(err)
}
defer rl.Close()
log.SetOutput(l.Stderr()) // let "log" write to l.Stderr instead of os.Stderr

go func() {
	for _ = range time.Tick(time.Second) {
		log.Println("hello")
	}
}()

for {
	line, err := rl.Readline()
	if err != nil { // io.EOF
		break
	}
	println(line)
}

Example with auto completion

import (
	"log"
	"github.com/chzyer/readline"
)

var completer = readline.NewPrefixCompleter(
	readline.PcItem("say",
		readline.PcItem("hello"),
		readline.PcItem("bye"),
	),
	readline.PcItem("help"),
)

rl, err := readline.New(&readline.Config{
	Prompt:       "> ",
	AutoComplete: completer,
})
if err != nil {
	panic(err)
}
defer rl.Close()

for {
	line, err := rl.Readline()
	if err != nil { // io.EOF
		break
	}
	println(line)
}

Shortcut

Meta+B means press Esc and n separately.
Users can change that in terminal simulator(i.e. iTerm2) to Alt+B

Shortcut in normal mode

Shortcut	Comment
`Ctrl`+`A`	Beginning of line
`Ctrl`+`B` / `←`	Backward one character
`Meta`+`B`	Backward one word
`Ctrl`+`C`	Send io.EOF
`Ctrl`+`D`	Delete one character
`Meta`+`D`	Delete one word
`Ctrl`+`E`	End of line
`Ctrl`+`F` / `→`	Forward one character
`Meta`+`F`	Forward one word
`Ctrl`+`G`	Cancel
`Ctrl`+`H`	Delete previous character
`Ctrl`+`I` / `Tab`	Command line completion
`Ctrl`+`J`	Line feed
`Ctrl`+`K`	Cut text to the end of line
`Ctrl`+`L`	Clean screen (TODO)
`Ctrl`+`M`	Same as Enter key
`Ctrl`+`N` / `↓`	Next line (in history)
`Ctrl`+`P` / `↑`	Prev line (in history)
`Ctrl`+`R`	Search backwards in history
`Ctrl`+`S`	Search forwards in history
`Ctrl`+`T`	Transpose characters
`Meta`+`T`	Transpose words (TODO)
`Ctrl`+`U`	Cut text to the beginning of line
`Ctrl`+`W`	Cut previous word
`Backspace`	Delete previous character
`Meta`+`Backspace`	Cut previous word
`Enter`	Line feed

Shortcut in Search Mode (Ctrl+S or Ctrl+r to enter this mode)

Shortcut	Comment
`Ctrl`+`S`	Search forwards in history
`Ctrl`+`R`	Search backwards in history
`Ctrl`+`C` / `Ctrl`+`G`	Exit Search Mode and revert the history
`Backspace`	Delete previous character
Other	Exit Search Mode

Shortcut in Complete Select Mode (double Tab to enter this mode)

Shortcut	Comment
`Ctrl`+`F`	Move Forward
`Ctrl`+`B`	Move Backward
`Ctrl`+`N`	Move to next line
`Ctrl`+`P`	Move to previous line
`Ctrl`+`A`	Move to the first candicate in current line
`Ctrl`+`E`	Move to the last candicate in current line
`Tab` / `Enter`	Use the word on cursor to complete
`Ctrl`+`C` / `Ctrl`+`G`	Exit Complete Select Mode
Other	Exit Complete Select Mode

Tested with

Environment	$TERM
Mac OS X iTerm2	xterm
Mac OS X default Terminal.app	xterm
Mac OS X iTerm2 Screen	screen
Mac OS X iTerm2 Tmux	screen
Ubuntu Server 14.04 LTS	linux
Centos 7	linux
Windows 10	-

Notice:

Ctrl+A is not working in screen because it used as a control command by default

If you test it otherwhere, whether it works fine or not, please let me know!

Feedback

If you have any question, please submit an GitHub Issues and any pull request is welcomed :)

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