nodejs Node.js fs.fchown()函数

Node.js fs.fchown()函数

原文:https://www.geeksforgeeks.org/node-js-fs-fchown-function/

fs.fchown()方法用于更改给定文件描述符的所有者和组。该功能接受用户 id 和组 id，可用于设置各自的所有者和组。它有一个回调函数，如果函数失败，它会返回任何可能出现的错误。

语法:

fs.fchown( fd, uid, gid, callback )

参数:该方法接受上述四个参数，如下所述:

FD: is an integer, which indicates that the file descriptors of the owner and group files need to be changed.
uid: is a number representing the user id corresponding to the owner to be set.
Gid: is a number representing the group ID corresponding to the group to be set.
Callback: is a function that will be called when the method is executed.
- err: If the method fails, this error will be thrown.

下面的例子说明了 Node.js 中的 fs.fchown()方法:

示例 1: 本示例显示了所有者的设置。

// Node.js program to demonstrate the
// fs.fchown() method

// Import the filesystem module
const fs = require('fs');

let fd = fs.openSync("example_file.txt", "r");

// Set the owner to a new one keeping the group same
// New owner is "geek" with user id 1027
// The old group is "xubuntu" with group id 999
fs.fchown(fd, 1027, 999, (error) => {
  if (error)
    console.log("Error Code:", error);
  else
    console.log("uid and gid set successfully");
});

运行代码前:

xubuntu@xubuntu: ~/Desktop/fs-fchown$ ls -l
total 8
-rw-rw--w- 1 xubuntu xubuntu 4 Apr 26 02:08 example_file.txt
-rw-rw-r-- 1 xubuntu xubuntu 290 Apr 26 02:08 index.js

代码输出:

Given uid and gid set successfully

运行代码后:

xubuntu@xubuntu: ~/Desktop/fs-fchown$ ls -l
total 8
-rw-rw--w- 1 geek xubuntu 4 Apr 26 02:08 example_file.txt
-rw-rw-r-- 1 xubuntu xubuntu 290 Apr 26 02:08 index.js

示例 2: 此示例显示了组的设置。

// Node.js program to demonstrate the
// fs.fchown() method

// Import the filesystem module
const fs = require('fs');

let fd = fs.openSync("example_file.txt", "r");

// Set the owner to a new one keeping the group same
// New owner is "raj" with user id 1025
// New group is "author" with group id 1031
fs.fchown(fd, 1025, 1031, (error) => {
  if (error)
    console.log("Error Code:", error);
  else
    console.log("uid and gid set successfully");
});

运行代码前:

xubuntu@xubuntu: ~/Desktop/fs-fchown$ ls -l
total 8
-rw-rw--w- 1 xubuntu xubuntu 4 Apr 26 02:08 example_file.txt
-rw-rw-r-- 1 xubuntu xubuntu 290 Apr 26 02:08 index.js

代码输出:

Given uid and gid set successfully

运行代码后:

xubuntu@xubuntu: ~/Desktop/fs-fchown$ ls -l
total 8
-rw-rw--w- 1 raj author 4 Apr 26 02:08 example_file.txt
-rw-rw-r-- 1 xubuntu xubuntu 290 Apr 26 02:08 index.js

参考:https://nodejs . org/API/fs . html # fs _ fs _ fchown _ FD _ uid _ GID _ callback