Add Windows support

README.md

@@ -8,6 +8,7 @@
 - Deduplication
 - Format check
 - `SUID` safe!
+- Supports *NIX (Linux & macOS) and Windows
 
 ## Usage
 

main.go

@@ -5,14 +5,16 @@ import (
 	"net"
 	"os"
 	"regexp"
+	"runtime"
 	"strings"
 	"time"
 )
 
 func main() {
 	targetIP, domains := parseArgs()
+	targetFile := getHostsPath()
 	motd()
-	process(targetIP, domains)
+	process(targetFile, targetIP, domains)
 }
 
 func parseArgs() (net.IP, []string) {
@@ -45,12 +47,23 @@ func parseArgs() (net.IP, []string) {
 	return ip, os.Args[2:]
 }
 
-// process goes over the /etc/hosts and tries to best-fit the domain names for the IP
-func process(ip net.IP, domains []string) {
+// getHostsPath returns the path to the hosts file depending on the current operating system:
+//  /etc/hosts on *NIX,
+//  C:\Windows\system32\drivers\etc\hosts on WIN*.
+func getHostsPath() (string) {
+	if runtime.GOOS == "windows" {
+		return "C:\\Windows\\system32\\drivers\\etc\\hosts"
+	} else {
+		return "/etc/hosts"
+	}
+}
+
+// process goes over the targetFile and tries to best-fit the domain names for the IP
+func process(targetFile string, ip net.IP, domains []string) {
 	// Read file
-	bytesEtcHosts, readErr := os.ReadFile("/etc/hosts")
+	bytesEtcHosts, readErr := os.ReadFile(targetFile)
 	if readErr != nil {
-		fmt.Fprintf(os.Stderr, "Failed to read /etc/hosts: %s\n", readErr.Error())
+		fmt.Fprintf(os.Stderr, "Failed to read %s: %s\n", targetFile, readErr.Error())
 		os.Exit(1)
 	}
 	etcHosts := string(bytesEtcHosts)
@@ -108,9 +121,9 @@ func process(ip net.IP, domains []string) {
 
 	// Write out again
 	newHosts := strings.Join(lines, "\n")
-	writeErr := os.WriteFile("/etc/hosts", []byte(newHosts), 0o644)
+	writeErr := os.WriteFile(targetFile, []byte(newHosts), 0o644)
 	if writeErr != nil {
-		fmt.Fprintf(os.Stderr, "Failed to write /etc/hosts: %s\n", writeErr.Error())
+		fmt.Fprintf(os.Stderr, "Failed to write %s: %s\n", targetFile, writeErr.Error())
 		os.Exit(1)
 	}
 }
@@ -131,6 +144,6 @@ func motd() {
 		fmt.Println("         G H O S T         ")
 		fmt.Println(" your friendly helper with ")
 	}
-	fmt.Println(" /etc/hosts, written in Go!")
+	fmt.Printf(" %cetc%chosts, written in Go!\n", os.PathSeparator, os.PathSeparator) // technically not fully correct, but the MOTD can only be *that* wide, right?
 	fmt.Println("+-------------------------+")
 }