1.调用系统命令
exec包执行外部命令，它将os.StartProcess进行包装使得它更容易映射到stdin和stdout，并且利用pipe连接i/o
func Command(name string, arg ...string) *Cmd {}调用系统命令：
package main
import (
"os/exec"
"log"
"fmt"
)
func main() {
cmd := exec.Command("ls","-l")
out,err := cmd.CombinedOutput()//标准输出 标准错误 组合
//out, err := cmd.Output()
//Output()和CombinedOutput()不能够同时使用，
// 因为command的标准输出只能有一个，同时使用的话便会定义了两个，便会报错
if err != nil {
log.Fatal(err)
}
fmt.Println(string(out))
}2.交互式调用系统命令
package main
import (
"os/exec"
"bufio"
"fmt"
"log"
"time"
)
func main() {
cmd := exec.Command("ls","-l")
out,_ :=cmd.StdoutPipe() //StdoutPipe返回一个连接到command标准输出的管道pipe
if err := cmd.Start();err != nil {
log.Fatal("start error:%v",err)
}
f := bufio.NewReader(out)
for {
line,err := f.ReadString(‘\n‘)
if err != nil {
break
}
fmt.Print(line)
}
time.Sleep(time.Hour)
//cmd.Wait()
//Wait等待command退出，他必须和Start一起使用，
//如果命令能够顺利执行完并顺利退出则返回nil，否则的话便会返回error，其中Wait会是放掉所有与cmd命令相关的资源
}不加wait()会产生僵尸进程，3466 defunct 僵尸进程，wait收尸
go build cmd.go
./cmd
[[email protected] ]#ps -ef |grep cmd2
root 3466 2539 0 20:37 pts/0 00:00:00 ./cmd2
[[email protected] ]#ps -ef |grep ls
root 683 1 0 18:43 ? 00:00:21 /usr/bin/vmtoolsd
root 3470 3466 0 20:37 pts/0 00:00:00 [ls] <defunct>3.自制bash
package main
import (
"bufio"
"fmt"
"os"
"os/exec"
"strings"
)
func main() {
host, _ := os.Hostname()
prompt := fmt.Sprintf("[[email protected]%s]$ ", host)
r := bufio.NewScanner(os.Stdin)
//r := bufio.NewReader(os.Stdin)
for {
fmt.Print(prompt)
if !r.Scan() {
break
}
line := r.Text()
// line, _ := r.ReadString(‘\n‘)
// line = strings.TrimSpace(line)
if len(line) == 0 {
continue
}
args := strings.Fields(line)
cmd := exec.Command(args[0], args[1:]...)
cmd.Stdin = os.Stdin
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
err := cmd.Run()
if err != nil {
fmt.Println(err)
}
}
}4.管道pipe
package main
import (
"fmt"
"io"
"log"
"os"
"os/exec"
"strings"
)
func main() {
line := "ls | grep f"
cmds := strings.Split(line, "|")
s1 := strings.Fields(cmds[0])
s2 := strings.Fields(cmds[1])
fmt.Println(s1)
fmt.Println(s2)
r, w := io.Pipe()
cmd1 := exec.Command(s1[0], s1[1:]...)
cmd2 := exec.Command(s2[0], s2[1:]...)
//cmd1 := exec.Command("ls")
//cmd2 := exec.Command("grep","f")
cmd1.Stdin = os.Stdin
cmd1.Stdout = w
cmd2.Stdin = r
cmd2.Stdout = os.Stdout
cmd1.Start()
cmd2.Start()
log.Print("start")
cmd1.Wait()
cmd2.Wait()
}