RHCSA4

get help （4 In terms of ）
1 --help

2 man file
man + command
q Key to exit

lookup
/+ keyword
n Match keywords down
N Match keywords up
G Jump to the tail
g Jump to the head

3 info
Use documentation for software
example ：pinfo tar

4 /usr/share/doc

I / O redirection and pipeline
Output to the screen to other places is called redirection

example ：echo aaa>file1 replace content
echo aaa>>file1 Additional content

Standard output redirection >
Standard error redirection 2>

find lookup
find / -name xx Find the whole thing xx

| Pipe,
The previous one is the output of the next one

vim Editor
Ordinary users vi Is equivalent to vim
vim You can create a new file

i,a Enter insertion mode
esc Return to command mode
v Enter visual mode

Command mode
yy Copy the current row
xyy Copy x That's ok
dd Delete a line
xdd Delete x That's ok
p Paste

：wq！ Save and exit
：q! To force out of
set nu According to the line Numbers