Learning experience of Linux (4)--first login and online Help man page

This section begins with a formal introduction to some Linux directives and introduces the differences between the GUI and the text interface.

1. Linux Preset 6 terminal to let the login, switch the way is Ctrl+alt+f1~f6, in addition F7 into the graphical interface, that is, we generally install Ubuntu or CentOS will enter the interface. The following will be detailed introduction of these kinds of terminal, the total can be divided into a graphical interface and non-graphical interface, if you want to enter the graphical interface from a non-graphical interface, you can enter the STARTX command in the terminal.

2. To unregister the system, the command is exit.

3. Enter the instruction in one line if it is too long, you can use the backslash \ To jump off the enter symbol, so that the instruction continues to the next line, but pay attention to! After the backslash is immediately followed by special characters, to jump off!

4. Display the current language: Echo $LANG

Modified language: Lang=en_us

5. Display Date: Focus on date +%y/%m/%d/%h:%m, the date format displayed is 2012/3/2/14:35

6. Display October 2009 Calendar: Cal 10 2009

7. When using the BC command to calculate the arithmetic, the default division sign is rounded, if you want to output decimals, you must add the instruction Scale=number before the calculation, where number indicates that several decimal points are displayed, enter quit to exit BC

8. Another important function of Linux (convenience) is a function, tab is followed by a string of instructions after the first word, indicating that the command is filled, followed by a string of instructions after the second word, the file is filled.

9. Ctrl + C means that the current program is interrupted and Ctrl+d indicates exiting the terminal.

Man (men) for query purposes, any instructions you are not familiar with can be solved by man, of course, there is a lot of real content, you can use/string to search for the desired string (down search). Use? String to search for the desired strings. Press Q to exit the man query.

11. The ultra-simple document editor is the Nano, using the Nano 1.txt, if there is no 1.txt, create a new one.

12. Restart, shutdown: Reboot,halt,poweroff

13. The following is the main introduction of the shutdown this directive.

Shutdown-h now: Turn off the machine immediately

Shutdown-h 20:25:20:25 shutdown

Shutdown-h + 10: Shutdown in 10 minutes

Shutdown-r Now: Restart immediately

Shutdown-r +30 ' The system will reboot ': Another 30 minutes to remind users to restart

Shutdown-k now ' the system will reboot ': issue only warning messages, not shutdown

14. In addition, since some instructions are executed when the contents of the file are kept in memory and not written to the hard disk, it is recommended to do the following before restarting in order to avoid a sudden shutdown that results in data not being saved: Sync;sync;sync;reboot

RunLevel: Run level 0--power off, run levels 3--Plain text mode, run status 5--with graphics interface mode, run, 6--restart

Learning experience of Linux (4)--first login and online Help man page