Linux command-grep

2. Command format:
   

   grep [options] Find condition directory file

4. Command function:

   For filtering, searching for specific characters

5. Common options:

   -A (number) displays the (number) row after the line, in addition to the line that matches the criteria

   - B (number) displays the line before the line, in addition to the line that matches the criteria

   - C (number) displays the front and back (number) lines of the row, in addition to the line that matches the criteria

   -I ignore case when searching

   - v show rows that do not contain criteria

   - n Displays the row where the condition is located and lists the line number of the row

6. Common examples:

   Example one: Filtering out the specified process sshd

   Command: PS aux | grep sshd

   Example two: Filter out the file with the keyword "Zhe" line, and display the line number of these lines

   Command: grep-n "the" file

   Example three: Filter out the file "a" begins with "a" line, ending with "Z"

   Command: grep "^a" file | grep "z$"

   Example four: Blank lines in file files are not displayed

   Command: grep-v "^$" file
   

Linux command-grep