Linux System Command 50

Installation and Login commands: Login, shutdown, halt, reboot, install, mount, Umount, Chsh, exit, last;
Document processing commands: File, mkdir, grep, DD, find, MV, LS, diff, Cat, ln;
System Management Related commands: DF, top, free, quota, at, LP, AddUser, Groupadd, Kill, crontab;
Network operation commands: Ifconfig, IP, ping, netstat, Telnet, ftp, route, Rlogin, RCP, finger, mail, nslookup;
System security Related commands: passwd, Su, umask, Chgrp, chmod, Chown, chattr, sudo ps, who;
Other commands: Tar, unzip, Gunzip, Unarj, Mtools, man, Unendcode, UUDecode.

(1) Login

2. Use
Login's role is to log on to the system, and its use rights are for all users.
2. Format
Login [name][-p][-h host name]
3. Main parameters
-P: Notifies login to maintain the current environment parameters.
-H: Used to transfer user names between remote logins.

(2) Shutdown
1. Role
The role of the shutdown command is to shut down the computer, and its use rights are super users.
2. Format
Shutdown [-H][-I][-K][-M][-T]
3. Important Parameters
-T: Tell the INIT program how long it will shut down before changing to another runlevel.
-K: Not really shut down, just send a warning signal to each login.
-H: Power off after shutting down the machine.
-c:cancel Current process cancels the currently executing shutdown program. So this option certainly does not have a time parameter, but you can enter a message to interpret, and this information will be sent to each user.
-F: Forces fsck to restart the computer.
-time: Set the time before shutting down the machine.
-M: Change the system to single-user mode.
-I: Displays system information when shutting down.
4. Command description
The shutdown command can safely shut down the system. It is dangerous for some users to shut down the Linux system in a way that directly shuts off the power supply. Because Linux, unlike Windows, runs many processes in the background, forcing a shutdown can cause data loss to the process, leave the system in an unstable state, or even damage the hardware device (hard disk) in some systems. Using the shutdown command before the system shuts down, the system administrator notifies all logged-in users that the system is shutting down and the login command is frozen, that is, the new user can no longer log on.

Linux System Command 50