Rhcsa day 3

1. Sum up vim Of the three modes, the commands you think are practical

vim Command mode of ：

dd Deletes the line where the cursor is located

G Jump to the end of the document

gg Jump to the beginning of the document

yy Copy

cc shear

p Paste （ Paste on the next line of the cursor ）

u Undo to the left （ Return to the last editing status ）

ctrl+r redo （ Undo right , Return to recent edits

vim Insert mode for ：

o       Enter insertion mode , Add content on the next line of the cursor
a       Insert content after cursor
s     Delete cursor character , Enter insertion mode

vim Last line mode of ：

q sign out

q!     Forced exit
wq     Save and exit

wq!     Forced save exit
x        Jump to the first place x That's ok     

/ keyword Quickly match the content of the line where the keyword is located

2. stay /opt Create a temporary directory under the directory tmp;

Create a file in the temporary directory , The file named a.txt;

take a.txt Copy it into b.txt; take b.txt Change its name to c.txt;

Create symbolic links , The linked file name is linkc.txt;

3.

application vi Command in /tmp Create files under folders , file name newfile. stay newfile Enter the date and time on the first line

take /boot/grub2/grub.cfg The contents of the document are read into newfile In the document （ On the next line of the date, i.e 2 That's ok

Find documents that contain # The line of the sign character , Delete entire line

  Turn on VI Line number prompt function

 

  Move the cursor to 5 That's ok , And in the first place 5 A new blank line is generated after the line 6 That's ok

  Modify the content . Will all timeout=5, Change to time=30（%s /timeout=5/timeout=30）

  All... In the entire document root The character is changed to admin character (%s /root/admin)

  Copy No 1 The date and time content of the line to the end of the document
(1.gg Back to the first line 2.yy Copy 3.G Cursor movement last line 4.$ Move to the end of the last line 5.pp Paste ）

Save the document , Save the document again as /boot/newfile2, sign out VI Editor

  Tail mode w! preservation

Input w/boot/newfile2

q!

4. Copy user profile to /opt Under the table of contents
see /opt/mima File first 6 That's ok

5.  Statistics show user profiles nologin Number of occurrences

6. Displays the total number of users in the system

7. Set the system time （ Minutes and seconds ） write in time file

8.history The system command history can be displayed , Count the top three with the highest command frequency of the current system .（ The command repeats three more commands ）