Chmod 备忘清单
这份快速参考备忘单提供了文件权限的简要概述，以及 chmod 命令的操作
入门
语法
示例
递归更改文件和目录
chmod 命令代表“更改模式”
Chmod 生成器
权限：
Chmod 生成器允许您以数字和符号的形式快速、直观地生成权限。
通用权限
| 命令 |
s |
含义 |
400 |
r-------- |
仅所有者可读 |
500 |
r-x------ |
避免改变 |
600 |
rw------- |
可由用户更改 |
644 |
rw-r--r-- |
由用户读取和更改 |
660 |
rw-rw---- |
可由用户和组更改 |
700 |
rwx------ |
只有用户具有完全访问权限 |
755 |
rwxr-xr-x |
只能由用户更改 |
775 |
rwxrwxr-x |
群组共享模式 |
777 |
rwxrwxrwx |
每个人都可以做任何事 |
解释
dir 的权限分析
权限模式
| 权限 |
描述 |
八进制 |
十进制 |
--- |
没有权限 |
000 |
0 (0+0+0) |
--x |
执行 |
001 |
1 (0+0+1) |
-w- |
写 |
010 |
2 (0+2+0) |
-wx |
执行和写入 |
011 |
3 (0+2+1) |
r-- |
读 |
100 |
4 (4+0+0) |
r-x |
读取和执行 |
101 |
5 (4+0+1) |
rw- |
读和写 |
110 |
6 (4+2+0) |
rwx |
读取、写入和执行 |
111 |
7 (4+2+1) |
Objects
| 谁（缩写） |
含义 |
u |
用户 |
g |
组 |
o |
其它 |
a |
全部，和 ugo 一样 |
权限
| 缩写 |
权限 |
值 |
r |
读 |
4 |
w |
写 |
2 |
x |
执行 |
1 |
- |
没有权限 |
0 |
文件类型
| 缩写 |
文件类型 |
d |
目录 |
- |
常规文件 |
l |
符号链接 |
Chmod 示例
操作符
| Symbol |
Description |
+ |
添加 |
- |
删除 |
= |
设置 |
chmod 600
chmod 664
chmod 777
符号模式
拒绝所有人的执行权限。
向所有人授予读取权限。
使文件可由组和其他人读写。
使用户/所有者可执行 shell。
允许每个人读取、写入和执行文件并打开设置的 group-ID。
删除权限
要删除赋予文件的读写权限，请使用以下语法：
对于我们的文件 example.txt，我们可以通过运行以下命令使用 chmod for group 删除读写权限：
要从组中删除 chmod 读写权限，同时向 public/others 添加读写权限，我们可以使用以下命令：
但是，如果你想删除组和其他人的所有权限，你可以使用 go= 来代替：
可执行文件
chmod 754
Chmod 实践
SSH 权限
网络权限
批量更改
请参阅：命令替换
另见
<script type="text/javascript">
const reg_num = /^[0-7]{3}$/; // 一些正则表达式来检查 num 输入
const reg_let = /^([r\-]{1}[w\-]{1}[x\-]{1}){3}$/; // 一些正则表达式来检查文本输入
function checkBoxHandle() {
change_occured(true, false, false);
// get rid of bad input classes
document.getElementById('num').classList.remove('bad-input');
document.getElementById('let').classList.remove('bad-input');
}
window.addEventListener("DOMContentLoaded", function () {
// loop over all the check boxes
for (let i = 1; i < 10; i++) {
let checkBox = document.getElementById(`${i}`);
checkBox.addEventListener('change', function () {
change_occured(true, false, false);
// get rid of bad input classes
document.getElementById('num').classList.remove('bad-input');
document.getElementById('let').classList.remove('bad-input');
});
}
// the octal input
let num_input = document.getElementById('num');
let num_fn = function () {
// check for bad input
if (!reg_num.test(this.value)) {
this.classList.add('bad-input');
} else {
this.classList.remove('bad-input');
change_occured(false, true, false);
}
};
num_input.addEventListener('change', num_fn);
num_input.addEventListener('keyup', num_fn);
// the let input
let let_input = document.getElementById('let');
let let_fn = function () {
// check for bad input
if (!reg_let.test(this.value)) {
this.classList.add('bad-input');
} else {
this.classList.remove('bad-input');
change_occured(false, false, true);
}
};
let_input.addEventListener('change',let_fn);
let_input.addEventListener('keyup',let_fn);
});
/* SETUP
r-4-1 r-4-4 r-4-7
w-2-2 w-2-5 w-2-8
x-1-3 x-1-6 x-1-9
*/
// define a function that runs when a change occures
function change_occured(caller_was_check, caller_was_num, caller_was_let) {
let num1 = 0, num2 = 0, num3 = 0; // these are the three numbers for the octal
let perm_string = ''; // holds the permision string ex. rw-x--r--
if (caller_was_check) {
// loop over all the check boxes and get the permisions
for (let i = 1; i < 10; i++) {
let checkBox = document.getElementById(`${i}`);
if (checkBox.checked) { // if checked
let current_perm = check_to_octal_and_text(i);
perm_string += `${current_perm.perm_let}`;
if (i <= 3) {
num1 += current_perm.perm_num;
} else if (i <= 6) {
num2 += current_perm.perm_num;
} else {
num3 += current_perm.perm_num;
}
} else { // if not checked
perm_string += '-';
}
}
// set the permision input text
document.getElementById('let').value = perm_string;
document.getElementById('num').value = `${num1}${num2}${num3}`;
} else if (caller_was_num) {
// get the individual numbers
let num_input_val = document.getElementById('num').value;
num1 = num_input_val.substring(0, 1);
num2 = num_input_val.substring(1, 2);
num3 = num_input_val.substring(2, 3);
// set the checkboxes and get the perm string
perm_string += octal_to_check_and_txt(num1, 0); //Owner
perm_string += octal_to_check_and_txt(num2, 1); //Owner
perm_string += octal_to_check_and_txt(num3, 2); //Owner
// set the permision input text
document.getElementById('let').value = perm_string;
} else if (caller_was_let) {
// get the text input
let perm_text = document.getElementById('let').value;
num1 = text_to_check_and_octal(perm_text.substring(0, 3), 0)
num2 = text_to_check_and_octal(perm_text.substring(3, 6), 3)
num3 = text_to_check_and_octal(perm_text.substring(6, 9), 6)
// set the octal value
document.getElementById('num').value = `${num1}${num2}${num3}`;
}
}
// define a function to converts the checkbox # to the respective permissions
// returns perm_num, perm_let
function check_to_octal_and_text(check_num) {
let perm_num = 0;
let perm_let = '-';
switch (check_num) {
case 1:
case 4:
case 7:
perm_num = 4;
perm_let = 'r';
break;
case 2:
case 5:
case 8:
perm_num = 2;
perm_let = 'w';
break;
case 3:
case 6:
case 9:
perm_num = 1;
perm_let = 'x';
break;
default:
perm_num = 0;
perm_let = '-';
}
// return values
return {
perm_num,
perm_let
};
}
/**
Takes a number 1-7 and which class it is in:
0 = owner
1 = Group
2 = Public
Returns: perm text (ex. "rwx") and sets the appropriate checkboxes
*/
function octal_to_check_and_txt(octal_num, class_num) {
let perm_text = '';
let offset = class_num * 3;
switch (octal_num) {
case '1':
document.getElementById(`${1 + offset}`).checked = false;
document.getElementById(`${2 + offset}`).checked = false;
document.getElementById(`${3 + offset}`).checked = true;
perm_text = '--x';
break;
case '2':
document.getElementById(`${1 + offset}`).checked = false;
document.getElementById(`${2 + offset}`).checked = true;
document.getElementById(`${3 + offset}`).checked = false;
perm_text = '-w-';
break;
case '3':
document.getElementById(`${1 + offset}`).checked = false;
document.getElementById(`${2 + offset}`).checked = true;
document.getElementById(`${3 + offset}`).checked = true;
perm_text = '-wx';
break;
case '4':
document.getElementById(`${1 + offset}`).checked = true;
document.getElementById(`${2 + offset}`).checked = false;
document.getElementById(`${3 + offset}`).checked = false;
perm_text = 'r--';
break;
case '5':
document.getElementById(`${1 + offset}`).checked = true;
document.getElementById(`${2 + offset}`).checked = false;
document.getElementById(`${3 + offset}`).checked = true;
perm_text = 'r-x';
break;
case '6':
document.getElementById(`${1 + offset}`).checked = true;
document.getElementById(`${2 + offset}`).checked = true;
document.getElementById(`${3 + offset}`).checked = false;
perm_text = 'rw-';
break;
case '7':
document.getElementById(`${1 + offset}`).checked = true;
document.getElementById(`${2 + offset}`).checked = true;
document.getElementById(`${3 + offset}`).checked = true;
perm_text = 'rwx';
break;
default:
document.getElementById(`${1 + offset}`).checked = false;
document.getElementById(`${2 + offset}`).checked = false;
document.getElementById(`${3 + offset}`).checked = false;
perm_text = '---';
}
return perm_text;
}
/**
Takes 3 letters (r, w, x, - ex. 'rw-') and an offset (0,3,6)
Returns the octal num and sets the appropriate checkboxes
*/
function text_to_check_and_octal(letters, offset) {
let perm_num = 0; // the octal number to return
// add up the oct num and set the check boxes
for (let i = 0; i < 3; i++) {
current_let = letters.substring(i, i + 1);
if (current_let == 'r') {
document.getElementById(`${i + 1 + offset}`).checked = true;
perm_num += 4;
} else if (current_let == 'w') {
document.getElementById(`${i + 1 + offset}`).checked = true;
perm_num += 2;
} else if (current_let == 'x') {
document.getElementById(`${i + 1 + offset}`).checked = true;
perm_num += 1;
} else {
document.getElementById(`${i + 1 + offset}`).checked = false;
}
}
return perm_num;
}
</script>
