Go标准库01之os包

FileMode

常量(Constants)

const (
    O_RDONLY int = syscall.O_RDONLY // 值为0，以只读的方式打开
    O_WRONLY int = syscall.O_WRONLY // 值为1，以只写的方式打开
    O_RDWR   int = syscall.O_RDWR  // 值为2，以读写的方式打开
    O_APPEND int = syscall.O_APPEND // 值为1024，以追加的方式写入
    O_CREATE int = syscall.O_CREAT  // 值为64，如果文件不存在，将会新建
    O_EXCL   int = syscall.O_EXCL   // used with O_CREATE, file must not exist
    O_SYNC   int = syscall.O_SYNC   // open for synchronous I/O.
    O_TRUNC  int = syscall.O_TRUNC  // if possible, truncate file when opened.
)

const (
    SEEK_SET int = 0 // seek relative to the origin of the file
    SEEK_CUR int = 1 // seek relative to the current offset
    SEEK_END int = 2 // seek relative to the end
)

const (
    PathSeparator     = '\' // OS-specific path separator
    PathListSeparator = ';'  // OS-specific path list separator
)

变量(Variables)

var (
    ErrInvalid    = errors.New("invalid argument") // methods on File will return this error when the receiver is nil
    ErrPermission = errors.New("permission denied")
    ErrExist      = errors.New("file already exists")
    ErrNotExist   = errors.New("file does not exist")
    ErrClosed     = errors.New("file already closed")
)

var (
    Stdin  = NewFile(uintptr(syscall.Stdin), "/dev/stdin")
    Stdout = NewFile(uintptr(syscall.Stdout), "/dev/stdout")
    Stderr = NewFile(uintptr(syscall.Stderr), "/dev/stderr")
)

var Args []string

常用函数

Chdir()

func Chdir(dir string) error

package main
import "os"

func main() {
    os.Chdir("../")
    os.Chdir("home/hxxz")
}

Chmod()

func Chmod(name string, mode FileMode) error

Chown()

func Chown(name string, uid, gid int) error

Chtimes()

func Chtimes(name string, atime time.Time, mtime time.Time) error

Clearenv()

func Clearenv()

Environ()

func Environ() []string

fmt.Println(os.Environ())

Executable()

func Executable() (string, error)

Exit()

func Exit(code int)

Expand()

func Expand(s string, mapping func(string) string) string

mapping := func(s string) string {
   m := map[string]string{"str": "我会替换$str变量", "hello": "我会替换$hello变量"}
   return m[s]
}
    str := os.Expand("你好世界 $str $hello world", mapping) //替换字符串中的$xxx 变量
    fmt.Println(str)    //你好世界 我会替换$str变量 我会替换$hello变量 world
    path := os.ExpandEnv("gopath is $GOPATH") //替换字符串中的环境变量
    fmt.Println(path)   //gopath is /wide/gogogo

ExpandEnv()

func ExpandEnv(s string) string

Geteuid()

func Geteuid() int

Getuid()

func Geteuid() int

Getegid()

func Getegid() int

Getgid()

func Getegid() int

Getenv()

func Getenv(key string) string

Getgroups()

func Getgroups() ([]int, error)

Getpagesize()

func Getpagesize() int

Getpid()

func Getpid() int

Getppid()

func Getppid() int

Getwd()

func Getwd() (dir string, err error)

Hostname()

func Hostname() (name string, err error)

IsExist()

func IsExist(err error) bool

err := os.Mkdir("/hmoe", 0755)
fmt.Println(os.IsExist(err))    //true

IsNotExist()

func IsNotExist(err error) bool

IsPathSeparator()

func IsPathSeparator(c uint8) bool

IsPermission()

func IsPermission(err error) bool

Lchown()

func Lchown(name string, uid, gid int) error

Link()

func Link(oldname, newname string) error

LookupEnv()

func LookupEnv(key string) (string, bool)

//如果有环境变量v，内容为空
fmt.Println(os.Getenv("v"))     //返回`空`
fmt.Println(os.LookupEnv("v"))  //俩返回值，会返回`空`以及`true`
//如果不存在环境变量n
fmt.Println(os.Getenv("n"))     //返回`空`
fmt.Println(os.LookupEnv("n"))  //俩返回值，会返回`空`以及`false`

Mkdir()

func Mkdir(name string, perm FileMode) error

MkdirAll()

func MkdirAll(path string, perm FileMode) error

NewSyscallError()

func NewSyscallError(syscall string, err error) error

Readlink()

func Readlink(name string) (string, error)

Remove()

func Remove(name string) (string, error)

RemoveAll()

func RemoveAll(path string) error

Rename()

func Rename(oldpath, newpath string) error

err := os.Rename("main.go1", "main.go2")
err1 := os.Rename("pkg2", "pkg2.new")
err2 := os.Rename("../1.go", "2.go") // 这里会将1.go从上级目录直接移动到本级目录并重命名为2.go
err3 := os.Rename("/home/2.go2", "../1.go")

SameFile()

func SameFile(fi1, fi2 FileInfo) bool

Symlink()

func Symlink(oldname, newname string) error

TempDir()

func TempDir() string

Truncate()

func Truncate(name string, size int64) error

Unsetenv()

func Unsetenv(key string) error

文件操作

type File struct {
    *file // 定义struct类型的File文件，返回File的地址
}

type file struct {
    fd      int
    name    string
    dirinfo *dirInfo // nil unless directory being read
}

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