shell-reader

shell-reader

shell-reader is a really basic Go library to create simple shell environments for VT-1xx compatible terminals with command history navigation support. I personally had a need to be able to create a very simple shell to communicate with my services but found it difficult to implement simple features like navigating command history with arrow keys using the Go standard library. Other Go libraries I looked into were made for really complex terminal interfaces and I just wanted something super simple. When I started reading into what it takes to accept keys (like arrow up and down) and to communicate with VT-1xx compatible terminals, I decided to expose this feature set as this really simple library.

Installation

Install and update this go package with go get -u github.com/chris-tomich/shell-reader

Usage

There's a complete example of how to use the library in cmd/shell_demo/shell_demo.go but below is a bare minimum version.

The most important points to note in this example are -

1. The reader needs to have Close() run as NewReader sets the terminal to CBreakMode and failing to run Close() will mean the terminal remains in this mode.
2. shell.NewReader() shouldn't be called more than once in a single application. (Will look to fix this in the future)
3. shell.NewReader() sets up a channel that listens for a SIGINT and will cleanup appropriately. If a SIGKILL is called, there will be no cleanup and this could cause unexpected behaviour in the terminal. Restarting the terminal will fix these issues.

import "github.com/chris-tomich/shell-reader/shell"

	reader, _ := shell.NewReader()

	defer reader.Close()

	for {
		fmt.Printf("$ ")
		line, _ := reader.ReadLine()

		color.Green("%v\n", line)
	}