Summary of some useful Linux commands

some of the practical Linux Command Summary

1. Enable the Vim editor to automatically add line numbers when editing

echo "Set Nu" >>/etc/profile

2. Manually add line numbers in the Vim editor

When Vim is turned on, enter set nu in command line mode

3, when entering English words, the distance between each letter is very large

 
 4, when reading text, print lines that begin with spaces and # 
 Cp /etc/profile /exercise/test.txt 
 egrep -v  "^$ |  ^# " test.txt 
 
 5, print nth row 
 head -100 | tail -1     Print line 100th 
 or head -n 100 | tail -n 1 
 history | head -100  | tail -1   the 100th line of the print history, or 100th history 
 
 6, find the 10 most recently modified files in the  /  directory 
  ls  -1t / | head -n 10 
   
  7, empty file Abc.txt 
  echo > Abc.txt 
   or Cat/dev/null > Abc.txt 
  , 
  8, two useful Shortcuts 
   (1), ESC +.   Indicates that the previous command is displayed in the command window (plus not counting the keys) 
   (2), CD-      switch to the previous directory 
   
  9, Sort by the 3rd column of the printed thing, And the previous 5 lines are displayed. 
  cat-n/etc/passwd | sort-nk 3| head-n 5 
 

650) this.width=650; "src=" Https://s1.51cto.com/wyfs02/M02/91/AF/wKiom1j3apGQ0pYqAABLO19xuVE839.png "title=" Sort.png "width=" "height=" "border=" 0 "hspace=" 0 "vspace=" 0 "style=" width:700px;height:110px; "alt=" Wkiom1j3apgq0pyqaablo19xuve839.png "/>

"Cat-n to show line numbers, and after sorting by the 3rd column, the preceding line numbers also change"

10, add line number

(1), when opened with the Vim text editor, the method of displaying the line number:

In command-line mode: Set Nu

or echo ' Set Nu ' >>/ETC/VIMRC again Source/etc/profile

(2), when displaying a text document, precede the text document with the line number method:

Cat-n filename

or awk ' $0=nr ': ' $ ' filename

"Both just change the screen output and do not change the source file"

(3), add the source file inside the line number

cat-n filename > filename1

CP filename1 FileName

Note: The method is old and constantly updated

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Summary of some useful Linux commands