2019-2020-1 Student ID 20199323 "Linux kernel principle and Analysis" in the first week of operation

problem

The difference between the terminal and pseudo-terminal?
Physical terminal is a terminal; pseudo-terminal is a virtual terminal, such as / dev / ptypn, / dev / ttypn (n is a nonnegative integer), and they are in pairs, you write end, it can be read from the other end, similar to in the pipeline. X window and the pseudo-terminal and telnet Telnet application, these logical entities log a pair of virtual terminal; a terminal and the terminal is genuine, such as printers, video terminals (display / keypad) and the like.

Content summary

Linux command line shortcuts

Ctrl + d keyboard entry or exit end of the terminal
Ctrl + s pause the current program, press any key to resume operation after a pause
Ctrl + z into the current program running in the background, the command to return to the foreground FG
ctrl + A move the cursor to the first input line corresponds Home key
Ctrl + e move the cursor to an input end of a line, corresponding to the end key
Ctrl + k deleted from the cursor position to the end of the line
+ Backspace delete Previous Alt a word
Shift + PgUp terminal will scroll up
Shift + PgDn terminal scroll down the
Ctrl + c Kill the current program
Tab command completion

User rights management

Open the terminal who am I with, or who mom likes

who frequently used parameters
-a printing can print all
-d dead printing process
-m i with AM, the MOM Likes
-q print and the number of users currently logged on user name
-u Print login user information
-r print run level

its The user may switch to a user, the user needs to enter the target when performing password
udo Can run cmd command privilege level, you need to belong to the current user sudo group, and the need to enter the current password of the user
su - Command is switching users, but will also change the environment variables to the target user's environment variables

The basic operation of Linux directory

touch new blank file
mkdir new directory
cp (copy) command to copy a file to the specified directory cp test father / son / grandson
replicate directory successfully copied to the directory or the need to add -r -R parameter indicates recursive copy
rm (remove files or directories ) command to delete a file
rm -f test if you want to ignore this prompt, delete files, you can use the -f option to force deletion:
Like replicate the directory you want to delete a directory, but also need to add -r or -R parameter