This tutorial explains Linux “less” command, options and its usage with examples.
Usage:
less [options] file_name
* Less is a program similar to more but which allows backward movement in the file as well as forward movement.
* less does not have to read the entire input file before starting, so with large input files it starts up faster than text editors like vi.
* Less uses termcap (or terminfo on some systems), so it can run on a variety of terminals.
The navigation keys in less command are similar to Vim editor. In this article, We will look at few less command navigation and other operations
related to it.
1. To open the file(less file_name):
sanfoundry-> less sample.txt Line 1 Hi i am a good boy. I am x . Be cool and calm Happy birthday I am Bond 00 7 Eurekaa !!! I Got it ! Yes No NOoooooooo Yesssssssssssssss yes sample.txt (END)
In order to quit from the prompt press “q” from the ketboard.
2. To Clear screen before displaying(less -c file_path):
sanfoundry-> less sample.txt Line 1 Hi i am a good boy. I am x . Be cool and calm Happy birthday I am Bond 00 7 Eurekaa !!! I Got it ! Yes No NOoooooooo Yesssssssssssssss yes ~ ~ ~ ~ .. sample.txt (END)
It clears the screen and shown only the contents of the file.
3. To Starts up the file from the given number(less +number file_path):
sanfoundry-> less +4 sample.txt Be cool and calm Happy birthday I am Bond 00 7 Eurekaa !!! I Got it ! Yes No NOoooooooo Yesssssssssssssss yes ~ ~ ~ ~ .. sample.txt (END)
4. To see large outputs one-screen-full at a time(command | less):
sanfoundry-> ls -la | less drwxr-xr-x 2 root root 4096 Apr 1 2012 .wireshark drwxrwxr-x 4 himanshu himanshu 4096 Jun 30 01:33 workspace -rw------- 1 himanshu himanshu 137 Jul 1 18:20 .Xauthority -rw------- 1 himanshu himanshu 3286 Jul 1 18:34 .xsession-errors -rw------- 1 himanshu himanshu 5556 Jul 1 16:46 .xsession-errors.old
Now let us see some Tips for effective navigation in less command
keyboard shortcuts for “less”
* [Arrows]/[Page Up]/[Page Down]/[Home]/[End]: Navigation. * [Space bar]: Next page. * b: Previous page. * ng: Jump to line number n. Default is the start of the file. * nG: Jump to line number n. Default is the end of the file. * /pattern: Search for pattern. Regular expressions can be used. * n: Go to next match (after a successful search). * N: Go to previous match. * ‘^ or g: Go to start of file. * ‘$ or G: Go to end of file. * s: Save current content (got from another program like grep) in a file. * =: File information. * F: continually read information from file and follow its end. Useful for logs watching. Use Ctrl+C to exit this mode. * -option: Toggle command-line option -option. * h: Help. * q or zz: Quit.
Forward Search Navigation
* / – 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 Navigation
* ? – search for a pattern which will take you to the previous occurrence. * n – for next match in forward * N – for previous match in backward
Line Navigation
* j – navigate forward by one line * k – navigate backward by one line
Screen Navigation
* CTRL+D – forward half window * CTRL+U – backward half window * CTRL+F – forward one window * CTRL+B – backward one window
Count numbers as options
* 5j – 5 lines forward. * 10k – 10 lines backward.
Some more less options
* :p - Examine the previous file in the command line list. * :d - Remove the current file from the list of files. * v – using the configured editor edit the current file. * &pattern – display only the matching lines, not all. * CTRL+G – show the current file name along with line, byte and percentage statistics. * mx – mark the current position with the letter ‘x’. * ‘x – go to the marked position ‘x’.
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