ANSI - A Colorful Formatter for Go

Ever wanted colorful output from your Golang CLI projects, but don't want to have to muck up your codebase with unsightly ANSI escape sequences?

Then this is the module for you!

Usage

go-ansi provides a drop-in replacement for fmt.Printf and friends that recognized an additional set of formatter flags for colorizing output.

import (
  fmt "github.com/jhunt/go-ansi"
)

func main() {
    err := DoSomething()
    if err != nil {
        fmt.Printf("error: @R{%s}", err)
    }
}

ansi.Fprintf, ansi.Sprintf and ansi.Errorf behave similarly, exporting the exact same call signature as their fmt bretheren, but handling the ANSI color sequences for you.

Formatting Codes

The colorizing formatting codes all look like this:

@ <color> { <text> }

(for the image-averse and search engines:)

  @k is Black         @K is Black (bold)
  @r is Red           @R is Red (bold)
  @g is Green         @G is Green (bold)
  @y is Yellow        @Y is Yellow (bold)
  @b is Blue          @B is Blue (bold)
  @m is Magenta       @M is Magenta (bold)
  @c is Cyan          @C is Cyan (bold)
  @w is White         @W is White (bold)

You can now also activate super-awesome RAINBOW mode with @*{...}

To Colorize or Not To Colorize?

Is that the question?

This library tries its hardest to determine whether or not colorized sequences should be honored or removed outright, based on the terminal-iness of the output medium. For example, if stdout is being redirected to a file, ansi.Printf will strip out the color sequences altogether.

Sometimes this is impossible. Specifically, for things like ansi.Errorf and ansi.Sprintf, the library has no idea whether or not the ultimate output stream even supports color code sequences. In those cases, you can check yourself, with ansi.CanColorize(io.Writer) -- it returns true if the io.Writer you passed it is hooked up to a terminal. ansi.ShouldColorize() is similar, except that it also returns true if ansi.ForceColor(true) has been called.

Contributing

1. Fork the repo
2. Write your code in a feature branch
3. Create a new Pull Request