Go language Programming-go language implementation file copy __go language programming

Introduction to the File Operations API New File

Func Create (name string) (file *file, err Error)
Creates a new file based on the file name provided, returns a file object with the default permission of 0666, and the returned file object is writable.

Func NewFile (fd uintptr, name string) *file
Creates the appropriate file based on the file descriptor, returns a file object to open the file

Func Open (name string) (file *file, err Error)
The method opens a file named name, but is read-only, and the internal implementation actually invokes OpenFile.

Func OpenFile (name string, flag int, perm uint32) (file *file, err Error)
Open the file named Name, flag is open way, read only, read and write, perm is permission to write files

Func (file *file) Write (b []byte) (n int, err Error)
Writes byte-type information to a file

Func (file *file) writeat (b []byte, off Int64) (n int, err Error)
Writes byte-type information at a specified location

Func (file *file) writestring (S string) (ret int, err Error)
Write string information to file read file

Func (file *file) Read (b []byte) (n int, err Error)
reading data to B

Func (file *file) readat (b []byte, off Int64) (n int, err Error)
Read data from off to delete files in B

Func Remove (name string) Error
Call this function to delete file code implementation with filename name

Package main

Import (
    "FMT"
    "io" "
    os"
)

func main () {
    list: = OS. Args

    If Len (list)!= 3 {
        FMT. Println ("Error: Missing parameters")
        return
    }
    srcname: = list[1]
    dstname: = list[2]
    srcfile, err1: = OS. Open (SrcName)
    dstfile, ERR2: = OS. Create (dstname)
    if err1!= nil | | err2!= NIL {fmt
        . Println ("err")
        return
    }
    defer srcfile.close ()
    defer dstfile.close ()
    buf: = Make ([]byte, 4* 1024)//4k buffer
    //core processing for
    {
        N, err: = Srcfile.read (BUF)
        If err!= nil {
            if err = = Io. EOF {//file read complete
                break
            }
            FMT. Println ("ERR:", err)
        }
        dstfile.write (Buf[:n])//Read how many to write}
}

Run Detection