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package main
import (
"bufio"
"flag"
"fmt"
"os"
"regexp"
"strings"
)
func init() {
highlightColor = red
flag.Var((*colorFlag)(&highlightColor), "c", fmt.Sprintf("highlight `color` %s", colorsChoices))
background = defaultColor
flag.Var((*colorFlag)(&background), "bg", fmt.Sprintf("background `color` default|%s", colorsChoices))
}
var (
highlightColor ansiColor
background ansiColor
)
//go:generate stringer -type=ansiColor -linecomment
type ansiColor int
const (
black ansiColor = iota
red
green
yellow
blue
magenta
cyan
white
defaultColor ansiColor = 9 // default
)
var colorsChoices = func() string {
nColors := white - black + 1
colors := make([]string, nColors)
for i := range nColors {
colors[i] = (black + i).String()
}
return strings.Join(colors, "|")
}()
func (c ansiColor) Foreground() int {
return 30 + int(c)
}
func (c ansiColor) Background() int {
return 40 + int(c)
}
type colorFlag int
func (c *colorFlag) Set(val string) error {
var ac ansiColor
switch strings.ToLower(val) {
case "default":
ac = defaultColor
case "black":
ac = black
case "red":
ac = red
case "green":
ac = green
case "yellow":
ac = yellow
case "blue":
ac = blue
case "magenta":
ac = magenta
case "cyan":
ac = cyan
case "white":
ac = white
default:
return fmt.Errorf("unknown color %q (valid choices: %s)", val, colorsChoices)
}
*c = colorFlag(ac)
return nil
}
func (c *colorFlag) String() string {
return ansiColor(*c).String()
}
func run() error {
args := flag.Args()
if len(args) == 0 {
fmt.Fprintf(os.Stderr, "hi: missing regexp to highlight\n")
flag.Usage()
}
if len(args) > 2 {
fmt.Fprintf(os.Stderr, "hi: too many positional arguments\n")
flag.Usage()
}
highlightRE, err := regexp.CompilePOSIX(args[0])
if err != nil {
return fmt.Errorf("invalid highlight regexp: %s\n", err)
}
foregroundColor := highlightColor.Foreground()
backgroundColor := background.Background()
scanner := bufio.NewScanner(os.Stdin)
for scanner.Scan() {
line := scanner.Text()
loc := highlightRE.FindStringIndex(line)
if loc == nil {
fmt.Printf("%s\n", line)
continue
}
startIdx, endIdx := loc[0], loc[1]
fmt.Printf("%s\033[%d;%dm%s\033[39;49m%s\n", line[:startIdx], foregroundColor, backgroundColor, line[startIdx:endIdx], line[endIdx:])
}
return scanner.Err()
}
func main() {
flag.Usage = func() {
fmt.Fprintf(os.Stderr, `Usage: hi [OPTION]... REGEXP
Highlight lines from standard input using the given regexp.
`)
flag.PrintDefaults()
fmt.Fprintf(os.Stderr, `
Examples:
echo 1\n2\n3 | hi ^2
journalctl | hi -bg cyan (E|e)rror | less
`)
os.Exit(2)
}
flag.Parse()
if err := run(); err != nil {
fmt.Fprintf(os.Stderr, "hi: %s\n", err)
os.Exit(1)
}
}
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