Liner is a command line editor with history. It was inspired by linenoise; everything Unix-like is a VT100 (or is trying very hard to be). If your terminal is not pretending to be a VT100, change it. Liner also support Windows.
Liner is intended for use by cross-platform applications. Therefore, the decision was made to write it in pure Go, avoiding cgo, for ease of cross compilation. Furthermore, features only supported on some platforms have been intentionally omitted. For example, Ctrl-Z is "suspend" on Unix, but "EOF" on Windows. In the interest of making an application behave the same way on every supported platform, Ctrl-Z is ignored by Liner.
Liner is released under the X11 license (which is similar to the new BSD license).
The following line editing commands are supported on platforms and terminals that Liner supports:
| Keystroke | Action |
|---|---|
| Ctrl-A, Home | Move cursor to beginning of line |
| Ctrl-E, End | Move cursor to end of line |
| Ctrl-B, Left | Move cursor one character left |
| Ctrl-F, Right | Move cursor one character right |
| Ctrl-Left, Alt-B | Move cursor to previous word |
| Ctrl-Right, Alt-F | Move cursor to next word |
| Ctrl-D, Del | (if line is not empty) Delete character under cursor |
| Ctrl-D | (if line is empty) End of File - usually quits application |
| Ctrl-C | Reset input (create new empty prompt) |
| Ctrl-L | Clear screen (line is unmodified) |
| Ctrl-T | Transpose previous character with current character |
| Ctrl-H, BackSpace | Delete character before cursor |
| Ctrl-W, Alt-BackSpace | Delete word leading up to cursor |
| Alt-D | Delete word following cursor |
| Ctrl-K | Delete from cursor to end of line |
| Ctrl-U | Delete from start of line to cursor |
| Ctrl-P, Up | Previous match from history |
| Ctrl-N, Down | Next match from history |
| Ctrl-R | Reverse Search history (Ctrl-S forward, Ctrl-G cancel) |
| Ctrl-Y | Paste from Yank buffer (Alt-Y to paste next yank instead) |
| Tab | Next completion |
| Shift-Tab | (after Tab) Previous completion |
Note that "Previous" and "Next match from history" will retain the part of
the line that the user has already typed, similar to zsh's
"up-line-or-beginning-search" (which is the default on some systems) or
bash's "history-search-backward" (which is my preferred behaviour, but does
not appear to be the default Up keybinding on any system).
package main
import (
"log"
"os"
"path/filepath"
"strings"
"github.com/peterh/liner"
)
var (
history_fn = filepath.Join(os.TempDir(), ".liner_example_history")
names = []string{"john", "james", "mary", "nancy"}
)
func main() {
line := liner.NewLiner()
defer line.Close()
line.SetCtrlCAborts(true)
line.SetCompleter(func(line string) (c []string) {
for _, n := range names {
if strings.HasPrefix(n, strings.ToLower(line)) {
c = append(c, n)
}
}
return
})
if f, err := os.Open(history_fn); err == nil {
line.ReadHistory(f)
f.Close()
}
if name, err := line.Prompt("What is your name? "); err == nil {
log.Print("Got: ", name)
line.AppendHistory(name)
} else if err == liner.ErrPromptAborted {
log.Print("Aborted")
} else {
log.Print("Error reading line: ", err)
}
if f, err := os.Create(history_fn); err != nil {
log.Print("Error writing history file: ", err)
} else {
line.WriteHistory(f)
f.Close()
}
}For documentation, see http://godoc.org/github.com/peterh/liner