Three commands for viewing logs in Linux and logs in linux

Three commands for viewing logs in Linux and logs in linux

First: View logs of real-time changes (more memory-consuming)

Most commonly used:

Tail-f filename (the last 10 rows by default, which is equivalent to adding the parameter-n 10)

Ctrl + c is the exit command

 

Other cases:

Tail-n 20 filename (display the last 20 rows of filename)

Tail-n + 5 filename (the file is displayed starting from row 5th)

 

Type 2: Search logs near keywords

Most commonly used:

Cat-n filename | grep "keyword"

　　　

Other cases:

Cat filename | grep-C 5 'keyword' (display the line matching the string in the log and the first and last five rows)

Cat filename | grep-B 5 'keyword' (show matching strings and the first five rows)

Cat filename | grep-A 5' keyword '(the matching string and the last 5 rows are displayed)

 

Third: Enter edit search: vi (vim)

1. Enter the vim editing mode: vim filename

2. enter "/keyword" and press enter to search

3. Find the next one and press "n ".

Exit: Press ESC, and then enter the number. vi will wait for us to enter the command at the bottom of the screen.

Wq! Save and exit;

Q! Do not save and exit;

 

Other cases:

/KeywordsNote: forward lookup: Press n to move the cursor to the next matching position.
?KeywordsNote: For reverse search, press shift + n to move the cursor to the next qualified