Linux command details-server management

1. Management Server Common commands

1. View online users: Who | Grep–v Root

2. Partition usage: df–h

3. View memory Information: free–m

4. View current time: Date

5. Write all events to the message:/bin/date >> Mail.cron

6. Execute the Sending message: (1.) Start mail server:/etc/init.d/sendmail start (2.) Send mail:/bin/mail–s subject users < Mail.cron

7. Timed Execution: Crontab–e

2.VI Editor

1. Set the line number: (1.) Bottom line mode:: Se nu (2.) ~/.VIMC Write set nu//Auto Add line number

2. View package path which VI Rpm–qf/bin/vi

3. Help: Man VI

3. File permissions

1.root user-created folders, how ordinary users create files in this folder

Workaround: Create two users, common group (1.) Groupadd group name (2.) gpassswd-a Zhangsan Group name (3.) to see if Zhangsan is within group: grep Group name/etc/group (4.) Change groups CHGRP Group name directory (5.) To give directory writable permissions: chmod g+w Directory

2. New file Permissions 644, no Execute permissions directory: 755

3. View User Rights Umask

4. SetUID: Normal user executes chmod u+s executable file with Admin user

5. Set the startup Vi/etc/inittab

6. When directory permissions are granted 777, users can only delete files that they have created and cannot delete files created by other users

7. Prevent accidental deletion, do not allow operation chattr +i file name can only be appended: chattr +a file name

8.visudo What's new Zhangsan helen= command to authorize root permissions

9. Sudo–l View all authorizations

10. Administrators authorize ordinary users to manage Apache:

(1.) Authorized User: Visudo Zhangsan helen=/apache/bin/apachectl,/bin/vi/apache/conf/httpd.conf

(2.) Authorized folder for normal users: Chown

11. Complex Permissions Control: ACL

(1.) Mount–o Remount,acl/home

(2.) setfacl-m u:zhangsan:rwx file name

(3.) View permissions: Getfacl file name

Linux command details-server management