# readline
[](LICENSE.md)
[](https://travis-ci.org/chzyer/readline)
[](https://godoc.org/github.com/chzyer/readline)
[](https://gitter.im/chzyer/readline?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge)
[](https://opencollective.com/readline#support)
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.
It can also provides shell-like interactives by using [flagly](https://github.com/chzyer/flagly) (demo: [flagly-shell](https://github.com/chzyer/flagly/blob/master/demo/flagly-shell/flagly-shell.go))
# Demo
Also works fine in windows
* [example/readline-demo](https://github.com/chzyer/readline/blob/master/example/readline-demo/readline-demo.go) The source code about the demo above
* [example/readline-im](https://github.com/chzyer/readline/blob/master/example/readline-im/readline-im.go) Example for how to write a IM program.
* [example/readline-multiline](https://github.com/chzyer/readline/blob/master/example/readline-multiline/readline-multiline.go) Example for how to parse command which can submit by multiple time.
* [example/readline-pass-strength](https://github.com/chzyer/readline/blob/master/example/readline-pass-strength/readline-pass-strength.go) A example about checking password strength, written by [@sahib](https://github.com/sahib)
# Todo
* Vi Mode is not completely finish
* More funny examples
* Support dumb/eterm-color terminal in emacs
# Features
* Support emacs/vi mode, almost all basic features that GNU-Readline is supported
* zsh-style backward/forward history search
* zsh-style completion
* Readline auto refresh when others write to Stdout while editing (it needs specify the Stdout/Stderr provided by *readline.Instance to others).
* Support colourful prompt in all platforms.
# Usage
* Import package
```
go get gopkg.in/readline.v1
```
or
```
go get github.com/chzyer/readline
```
* Simplest example
```go
import "gopkg.in/readline.v1"
rl, err := readline.New("> ")
if err != nil {
panic(err)
}
defer rl.Close()
for {
line, err := rl.Readline()
if err != nil { // io.EOF, readline.ErrInterrupt
break
}
println(line)
}
```
* Example with durable history
```go
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, readline.ErrInterrupt
break
}
println(line)
}
```
* Example with auto completion
```go
import (
"gopkg.in/readline.v1"
)
var completer = readline.NewPrefixCompleter(
readline.PcItem("say",
readline.PcItem("hello"),
readline.PcItem("bye"),
),
readline.PcItem("help"),
)
rl, err := readline.NewEx(&readline.Config{
Prompt: "> ",
AutoComplete: completer,
})
if err != nil {
panic(err)
}
defer rl.Close()
for {
line, err := rl.Readline()
if err != nil { // io.EOF, readline.ErrInterrupt
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`
Notice: `Meta`+`B` is equals with `Alt`+`B` in windows.
* 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!
## Who is using Readline
* [cockroachdb/cockroach](https://github.com/cockroachdb/cockroach)
* [youtube/doorman](https://github.com/youtube/doorman)
* [bom-d-van/harp](https://github.com/bom-d-van/harp)
* [abiosoft/ishell](https://github.com/abiosoft/ishell)
* [robertkrimen/otto](https://github.com/robertkrimen/otto)
# Feedback
If you have any questions, please submit a github issue and any pull requests is welcomed :)
* [https://twitter.com/chzyer](https://twitter.com/chzyer)
* [http://weibo.com/2145262190](http://weibo.com/2145262190)
# Backers
Love Readline? Help me keep it alive by donating funds to cover project expenses!
[[Become a backer](https://opencollective.com/readline)]
