Instructions for command usage related to System management in Linux

1.free

This command is used to view the current system memory usage, which can display the remaining and used physical memory, swap memory, shared memory, and kernel buffers in the system.

2. Shutdown

This command is used to shut down or enter a single maintenance mode.

3.data

The data command can display the date and time of the current system. The clock command can also be used to display the current date and time of the system (by default, ordinary users cannot perform the clock command and must log on with the root account). For example:

[Root@teacher root]$ Date

Monday, June 09:18:37 CST http://www.aliyun.com/zixun/aggregation/19058.html ">2003 Standard Time

[Root@teacher root]$ Clock

June 23, 2003 Monday 09:18 43 sec -0.832323 seconds

4.cal

This command displays a calendar or almanac on your computer. For example:

[Root@teacher root]# Cal

June 2003

Day 123456

1 2 3 4 5 6 7

8 9 10 11 12 13 14

15 16 17 18 19 20 21

22 23 24 25 26 27 28

29 30

[Root@teacher root]# cal–y parameter y display Almanac

5. Write

This command is used to send a message to a user in the system. If the user wants to exit the information sending status, press the combination key CTRL + C. For example:

[Root@teacher etc]# Write Root

Message from Root@teacheron pts/0 at 08:50 ...

Whar are you doing?

Whar are you doing?

EOF