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@@ -1 +1,88 @@
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-# 13.6 启动外部命令和程序
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+# 13.6 启动外部命令和程序
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+
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+os 包有一个 `StartProcess` 函数可以调用或启动外部系统命令和二进制可执行文件；它的第一个参数是要运行的进程，第二个参数用来传递选项或参数，第三个参数是含有系统环境基本信息的结构体。
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+
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+这个函数返回被启动进程的 id（pid），或者启动失败返回错误。
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+
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+exec 包中也有同样功能的更简单的结构体和函数；主要是 `exec.Command(name string, arg ...string)` 和 `Run()`。首先需要用系统命令或可执行文件的名字创建一个 `Command` 对象，然后用这个对象作为接收者调用 `Run()`。下面的程序（因为是执行 Linux 命令，只能在 Linux 下面运行）演示了它们的使用：
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+
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+示例 13.6 [exec.go](examples/chapter_13/exec.go)：
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+
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+```go
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+// exec.go
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+package main
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+import (
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+ "fmt"
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+ "os/exec"
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+ "os"
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+)
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+
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+func main() {
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+// 1) os.StartProcess //
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+/*********************/
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+/* Linux: */
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+env := os.Environ()
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+procAttr := &os.ProcAttr{
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+ Env: env,
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+ Files: []*os.File{
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+ os.Stdin,
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+ os.Stdout,
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+ os.Stderr,
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+ },
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+ }
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+// 1st example: list files
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+pid, err := os.StartProcess("/bin/ls", []string{"ls", "-l"}, procAttr)
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+if err != nil {
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+ fmt.Printf("Error %v starting process!", err) //
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+ os.Exit(1)
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+}
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+fmt.Printf("The process id is %v", pid)
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+```
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+
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+输出：
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+
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+``` go
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+The process id is &{2054 0}total 2056
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+-rwxr-xr-x 1 ivo ivo 1157555 2011-07-04 16:48 Mieken_exec
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+-rw-r--r-- 1 ivo ivo 2124 2011-07-04 16:48 Mieken_exec.go
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+-rw-r--r-- 1 ivo ivo 18528 2011-07-04 16:48 Mieken_exec_go_.6
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+-rwxr-xr-x 1 ivo ivo 913920 2011-06-03 16:13 panic.exe
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+-rw-r--r-- 1 ivo ivo 180 2011-04-11 20:39 panic.go
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+```
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+
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+```go
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+// 2nd example: show all processes
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+pid, err = os.StartProcess("/bin/ps", []string{"-e", "-opid,ppid,comm"}, procAttr)
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+if err != nil {
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+ fmt.Printf("Error %v starting process!", err) //
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+ os.Exit(1)
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+}
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+fmt.Printf("The process id is %v", pid)
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+
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+```
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+
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+```go
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+// 2) exec.Run //
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+/***************/
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+// Linux: OK, but not for ls ?
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+// cmd := exec.Command("ls", "-l") // no error, but doesn't show anything ?
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+// cmd := exec.Command("ls") // no error, but doesn't show anything ?
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+ cmd := exec.Command("gedit") // this opens a gedit-window
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+ err = cmd.Run()
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+ if err != nil {
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+ fmt.Printf("Error %v executing command!", err)
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+ os.Exit(1)
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+ }
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+ fmt.Printf("The command is %v", cmd)
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+// The command is &{/bin/ls [ls -l] [] <nil> <nil> <nil> 0xf840000210 <nil> true [0xf84000ea50 0xf84000e9f0 0xf84000e9c0] [0xf84000ea50 0xf84000e9f0 0xf84000e9c0] [] [] 0xf8400128c0}
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+}
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+// in Windows: uitvoering: Error fork/exec /bin/ls: The system cannot find the path specified. starting process!
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+
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+```
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+
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+
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+## 链接
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+
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+- [目录](directory.md)
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+- 上一节：[一种用闭包处理错误的模式](13.5.md)
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+- 下一节：[Go 中的单元测试和基准测试](13.7.md)
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dake