Go OS Package

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Package Mainimport ("FMT" "Io/ioutil" "OS" "Reflect" "Time"Func Main () {dir, _:=OS. GETWD () fmt. Println ("Dir:", dir) Err:= OS. Chdir ("D:/project/test2") dir, _=OS. GETWD () fmt. Println ("Dir:", dir)//parameter is case insensitive    //return empty string len (path) = 0 if no environment variable existsPath: = OS. Getenv ("Gopath") fmt. Println (PATH)//returns a valid group IDEgid: =OS. Getegid () fmt. Println ("Egid:", Egid)//return valid UIDEuid: =OS. Geteuid () fmt. Println ("Euid:", Euid) GID:=OS. Getgid () fmt. Println ("GID:", GID) UID:=OS. Getuid () fmt. Println ("UID:", UID)//Err:getgroups:not supported by WindowsG, err: =OS. GetGroups () fmt. Println (g,"Error", Err) pagesize:=OS. GetPageSize () fmt. Println ("PageSize:", pagesize) Ppid:=OS. Getppid () fmt. Println ("Ppid", Ppid)//FileMode, err: = OS. Stat ("Main.go")    //A file that does not exist returns GetFileAttributesEx Test2:the system cannot find the file specified.FileMode, err: = OS. Stat ("Main.go")    ifErr = =Nil {fmt. Println ("Filename:", FileMode. Name ()) fmt. Println ("Filesize:", FileMode. Size ()) fmt. Println ("Filemode:", FileMode. Mode ()) fmt. Println ("Modtime:", FileMode. Modtime ()) fmt. Println ("Is_dir", FileMode. Isdir ()) fmt. Println ("SYS", FileMode. Sys ())}Else{fmt. Println ("OS. Stat Error ", Err)} //Chmod is not supported under Windows.    //in Windows change is such a-rw-rw-rw-=-r--r--r--Err = OS. Chmod ("Main.go", 7777) fmt. Println ("Chmod:", err) FileMode, err= OS. Stat ("Main.go") fmt. Println ("Filemode:", FileMode. Mode ())//Access Time Modification timeErr = OS. Chtimes ("Main.go", time. Now (), time. Now ()) FMT. Println ("Chtime Error:", Err)//get all the environment variablesData: =OS. Environ () for_, Val: =range Data {fmt. Println (val)} fmt. Println ("---------End---environ----------------------") Mapping:=func (s string) string {m:= map[string]string{"xx": "Sssssssssssss",            "yy": "Ttttttttttttttt"}        returnM[s]} datas:= "Hello $xx blog Address $yy"//This function feels pretty useful .EXPANDSTR: =OS. Expand (datas, mapping) FMT. Println (EXPANDSTR) datas= "GOBIN PATH $gopaTh"// Case insensitiveFMT. Println (OS. Expandenv (datas)) hostname, ERR:=OS. Hostname () fmt. Println ("Hostname:", hostname) _, Err= OS. Open ("wwww.xx")    ifErr! =Nil {fmt. Println (OS. Isnotexist (Err)) fmt. PRINTLN (Err)} F, err:= OS. Open ("wwww.xx")    ifErr! = Nil &&!OS. Isexist (Err) {FMT. Println (F,"Not Exist")    }    //Two of all windows are trueFmt. Println (OS. Ispathseparator ('/') FMT. Println (OS. Ispathseparator ('\\') FMT. Println (OS. Ispathseparator ('.'))    //determine if the error returned is a permission issue    //func ispermission (err error) bool    //Not supported by WindowsErr = OS. Link ("Main.go", "Newmain.go")    ifErr! =Nil {fmt. PRINTLN (ERR)}varPathsep StringifOs. Ispathseparator (' \ \ ') {Pathsep= "\\"    } Else{pathsep= "/"} fmt. Println ("PathSeparator:", Pathsep)//Mkdirall creates all subordinate directories, and if not, create them.    //Mkdir Create a directory, if it is multi-level directory encountered has not been created will be an errorErr = OS. Mkdir (dir+pathsep+ "MD" +pathsep+ "MD" +pathsep+ "MD" +pathsep+ "MD" +pathsep+ "MD", OS. Modeperm)ifErr! =Nil {fmt. Println (OS. Isexist (ERR), err)} Err= OS. RemoveAll (dir + "MD\\MD\\MD\\MD\\MD")) fmt. Println ("Removall", Err)//Rename is actually implemented through MoveFile .Err = OS. Rename ("Main.go", "Main1.go") F1, _:= OS. Stat ("Main.go") F2, _:= OS. Stat ("Main1.go")    ifOS. Samefile (f1, F2) {fmt. Println ("The Sanme")    } Else{fmt. Println ("Not Same")    }    //OS. Setenv This function is very simple to set environment variablesEVN: = os. Getenv ("Wd_path") fmt. Println ("Wd_path:", EVN) Err= OS. Setenv ("Wd_path", "D:/project")    ifErr! =Nil {fmt. PRINTLN (ERR)} tmp, _:= Ioutil. TempDir (dir, "tmp") fmt. PRINTLN (TMP) TMP=OS. TempDir () fmt. PRINTLN (TMP) CF, err:= OS. Create ("Golang.go") Defer cf. Close () fmt. PRINTLN (Err) fmt. Println (reflect. ValueOf (f). Type ()) of, err:= OS. OpenFile ("Golang.goss", OS. O_rdwr|os. O_create|os. O_trunc, 0777) Defer of. Close () fmt. Println ("OS. OpenFile: ", err) oof, err:= OS. Open ("Golang.goss") defer oof. Close () fmt. Println ("OS. Open file: ", Oof. Fd ()) fmt. Println ("OS. Open ERR: ", err) oof. Close () R, W, err:=OS. Pipe () W.write ([]byte("1111"))    varBUF = make ([]byte, 4) R.read (BUF) fmt. Println (BUF) w.write ([]byte("2222")) R.read (BUF)//If you do not call W. Write (), R.read () will blockFmt. Println ("ssss--", buf) B:= Make ([]byte, 100) FF, _:= OS. Open ("Main.go") N, _:=ff. Read (b) fmt. PRINTLN (n) fmt. Println (String (B[:n]))//The second parameter, refers to, starts from the first readingN, _ = ff. ReadAt (b, 20) fmt. PRINTLN (n) fmt. Println (String (B[:n]))//get a list of files under a folderDirs, err: = OS. Open ("MD")    ifErr! =Nil {fmt. PRINTLN (ERR)} defer dirs. Close ()//parameter is less than or equal to 0, indicating that all files are read    //another function that only reads the file name    //FS, err: = dirs. Readdirname (0)FS, err: = dirs. Readdir (-1)    ifErr = =Nil { for_, File: =Range FS {fmt. Println (file. Name ())}}Else{fmt. Println ("Readdir:", Err)} //func (f *file) WriteString (S string) (ret int, err error)    //Write a String function prototype, which function is faster??     //P, _: = OS. Findprocess (628)    //FMT. PRINTLN (P)    //P.kill ()attr: = &OS. procattr{Files: []*OS. File{os. Stdin, OS. Stdout, OS. Stderr},}//parameters can also be written ' C:\windows\system32\notepad. EXE ' with inverted single quotesP, err: = OS. StartProcess ("C:\\windows\\system32\\notepad. EXE ", []string{" C:\\windows\\system32\\notepad. EXE "," D:/1.txt "}, attr) P.release () time. Sleep (1000000000) p.signal (OS. Kill) OS. Exit (10)}