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package main
import (
"bufio"
"fmt"
"os"
"os/exec"
"path"
"strconv"
"strings"
)
func main() {
stdin := bufio.NewReader(os.Stdin)
for {
fmt.Fprint(os.Stdout, "$ ")
in, err := stdin.ReadString('\n')
if err != nil {
fmt.Println(err.Error())
}
trim := strings.TrimSpace(in)
command := strings.Split(trim, " ")
switch command[0] {
case "exit":
Exit(command[1])
case "echo":
Echo(command[1:])
case "type":
Type(command[1])
case "pwd":
Pwd()
case "cd":
Cd(command[1])
default:
executable := exec.Command(command[0], command[1:]...)
executable.Stderr = os.Stderr
executable.Stdout = os.Stdout
err := executable.Run()
if err != nil {
fmt.Printf("%s: command not found\n", command[0])
}
}
}
}
func Cd(dir string) {
p := path.Clean(dir)
if !path.IsAbs(p) {
directory, _ := os.Getwd()
p = path.Join(directory, p)
}
err := os.Chdir(p)
if err != nil {
fmt.Printf("%s: No such file or directory\n", p)
}
}
func Pwd() {
dir, err := os.Getwd()
if err != nil {
fmt.Println(err.Error())
}
fmt.Println(dir)
}
func Echo(message []string) {
fmt.Println(strings.Join(message, " "))
}
func Exit(code string) {
exitCode, err := strconv.Atoi(code)
if err != nil {
fmt.Println(err.Error())
}
os.Exit(exitCode)
}
func Type(command string) {
switch command {
case "exit", "echo", "type":
fmt.Printf("%s is a shell builtin\n", command)
default:
env := os.Getenv("PATH")
paths := strings.Split(env, ":")
for _, path := range paths {
exec := path + "/" + command
if _, err := os.Stat(exec); err == nil {
fmt.Printf("%s is %s\n", command, exec)
return
}
}
fmt.Printf("%s not found\n", command)
}
}
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