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Less commands in UNIX

                                   Do more with Less command in Unix_______________________


1. Search Navigation

Once you’ve opened a log file (or any file) using less file-name, use the following keys to search. Please note that the match will be highlighted automatically by default.

Forward 

  • / – search for a pattern which will take you to the next occurrence.
  • n – for next match in forward
  • N – for previous match in backward

Backward 

  • ? – search for a pattern which will take you to the previous occurrence.
  • n – for next match in backward direction
  • N – for previous match in forward direction
Tip: If you dont bother about which direction the search is happening, and you want to search file path, or URL, such as “/home/amit/”, you can use backward search (?pattern) which will be handy as you don’t want to escape slashes each time.
Search Path
In forward: /\/home\/amit\/
In backward: ?/home/amit/

2. On Screen 

Use the following screen navigation commands while viewing large log files.
  • CTRL+F – forward one window
  • CTRL+B – backward one window
  • CTRL+D – forward half window
  • CTRL+U – backward half window

3.  Line navigation

In a smaller chunk of data, where you want to locate particular error, you may want to navigate line by line using these keys:
  • j – navigate forward by one line
  • k – navigate backward by one line

4.  Other Navigations

The following are other navigation operations that you can use inside the less pager.

  • G – go to the end of file
  • g – go to the start of file
  • q or ZZ – exit the less pager

5. Simulate tail -f inside less pager – Press F

Once you’ve opened a file using less command, any content that is appended to the file after that will not be displayed automatically. However, you can press Fless command will show the status ‘waiting for data‘. This is as similar to ‘tail -f’.

6. Less Command – Counting line


  • 10j – 10 lines forward.
  • 10k – 10 lines backward.
  • CTRL+G – show the current file name along with line, byte and percentage statistics.

7. Other useful Less Command Operations

  • v – using the configured editor edit the current file.
  • h – summary of less commands
  • &pattern – display only the matching lines, not all.

8. Open any types of files using less command

 less command to Open & view 10 different file types.

9. Less Command – Marked navigation

When you are viewing a large log file using less command, you can mark a particular position and return back to that place again by using that mark.
  • ma – mark the current position with the letter ‘a’,
  • ‘a – go to the marked position ‘a’.

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