"UNIX命令与shell编程:文件安全与权限探讨"
"Shell programming and Unix commands_opt1; Chapter 1 File Security and Permissions In order to prevent unauthorized access to your files, you can set permissions on files and directories, and also set default permissions for files when they are created. However, this is just a small part of the overall system security issue; downloading Chapter 1 File Security and Permissions In order to prevent unauthorized access to your files, you can set permissions on files and directories, and also set default permissions for files when they are created. However, this is just a small part of the overall system security issue. Here, we do not want to discuss all aspects of system security issues. We just want to introduce some basic file and directory security issues. This chapter contains the following: • File and directory permissions. • setuid. • chown and chgrp. • umask. • Symbolic links. The user who creates a file and belongs to the group owns the file. The owner of the file can set who has read, write, and execute permissions for the file. Of course, the root user or system administrator can change the settings for any ordinary user. Once a file is created, it has three types of access: 1) Read, which can display the contents of the file. 2) Write, which can edit or delete it. 3) Execute, if the file is a shell script or program. Depending on the user targeted, file permissions can be divided into three categories: 1) File owner, the user who created the file. 2) Same group users, any user in the user group who owns the file. 3) Other users, i.e. any user not belonging to the user group that owns the file. 1.1 File When you create a file, the system saves all the information about the file, including: • File location. • File type. • File length. • Who has access to the file. This is just a small part of the topic. There are many other things to consider, such as file permissions and how to change them. You can learn more about these topics in our online course."
![](https://csdnimg.cn/release/download_crawler_static/86333987/bg10.jpg)
![](https://csdnimg.cn/release/download_crawler_static/86333987/bg11.jpg)
![](https://csdnimg.cn/release/download_crawler_static/86333987/bg12.jpg)
![](https://csdnimg.cn/release/download_crawler_static/86333987/bg13.jpg)
![](https://csdnimg.cn/release/download_crawler_static/86333987/bg14.jpg)
剩余355页未读,继续阅读
![application/pdf](https://img-home.csdnimg.cn/images/20210720083512.png)
![pdf](https://img-home.csdnimg.cn/images/20210720083512.png)
![zip](https://img-home.csdnimg.cn/images/20210720083736.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/release/wenkucmsfe/public/img/green-success.6a4acb44.png)