exec

package standard library
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 Go to latest Published: Jun 2, 2016 License: BSD-3-Clause Imports: 11 Imported by: 265,708

Documentation

Overview

Package exec runs external commands. It wraps os.StartProcess to make it easier to remap stdin and stdout, connect I/O with pipes, and do other adjustments.

Note that the examples in this package assume a Unix system. They may not run on Windows, and they do not run in the Go Playground used by golang.org and godoc.org.

Index

Examples

Constants

This section is empty.

Variables

View Source 
var ErrNotFound = errors.New("executable file not found in $PATH")

ErrNotFound is the error resulting if a path search failed to find an executable file.

Functions

func LookPath 

func LookPath(file string) (string, error)

LookPath searches for an executable binary named file in the directories named by the PATH environment variable. If file contains a slash, it is tried directly and the PATH is not consulted. The result may be an absolute path or a path relative to the current directory.

Example 
package main

import (
	"fmt"
	"log"
	"os/exec"
)

func main() {
	path, err := exec.LookPath("fortune")
	if err != nil {
		log.Fatal("installing fortune is in your future")
	}
	fmt.Printf("fortune is available at %s\n", path)
}

Types

type Cmd 

type Cmd struct {
	// Path is the path of the command to run.
	//
	// This is the only field that must be set to a non-zero
	// value. If Path is relative, it is evaluated relative
	// to Dir.
	Path string

	// Args holds command line arguments, including the command as Args[0].
	// If the Args field is empty or nil, Run uses {Path}.
	//
	// In typical use, both Path and Args are set by calling Command.
	Args []string

	// Env specifies the environment of the process.
	// If Env is nil, Run uses the current process's environment.
	Env []string

	// Dir specifies the working directory of the command.
	// If Dir is the empty string, Run runs the command in the
	// calling process's current directory.
	Dir string

	// Stdin specifies the process's standard input.
	// If Stdin is nil, the process reads from the null device (os.DevNull).
	// If Stdin is an *os.File, the process's standard input is connected
	// directly to that file.
	// Otherwise, during the execution of the command a separate
	// goroutine reads from Stdin and delivers that data to the command
	// over a pipe. In this case, Wait does not complete until the goroutine
	// stops copying, either because it has reached the end of Stdin
	// (EOF or a read error) or because writing to the pipe returned an error.
	Stdin io.Reader

	// Stdout and Stderr specify the process's standard output and error.
	//
	// If either is nil, Run connects the corresponding file descriptor
	// to the null device (os.DevNull).
	//
	// If Stdout and Stderr are the same writer, at most one
	// goroutine at a time will call Write.
	Stdout io.Writer
	Stderr io.Writer

	// ExtraFiles specifies additional open files to be inherited by the
	// new process. It does not include standard input, standard output, or
	// standard error. If non-nil, entry i becomes file descriptor 3+i.
	//
	// BUG(rsc): On OS X 10.6, child processes may sometimes inherit unwanted fds.
	// https://golang.org/issue/2603
	ExtraFiles []*os.File

	// SysProcAttr holds optional, operating system-specific attributes.
	// Run passes it to os.StartProcess as the os.ProcAttr's Sys field.
	SysProcAttr *syscall.SysProcAttr

	// Process is the underlying process, once started.
	Process *os.Process

	// ProcessState contains information about an exited process,