Less Command: 10 Tips for Effective Navigation
the file to view in an editor). Less is similar to more command, but less
allows both forward and backward movements. Moreover, less don't require
to load the whole file before viewing. Try opening a large log file in Vim
editor and less — you'll see the speed difference.
The navigation keys in less command are similar to Vim editor. In this
article, let us look at few less command navigation and other operations
which will make you a better command line warrior.
1. Less Command – 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
/ – 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
? – 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/ramesh/", 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\/ramesh\/
In backward: ?/home/ramesh/
2. Less Command – Screen Navigation
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. Less Command – 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. Less Command – 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 F less command will show the status 'waiting for data'. This is
as similar to 'tail -f'.
Also, refer to our earlier article about how to view multiple logs files
using tail -f.
6. Less Command – Count magic
Similar to Vim editor navigation command, you can give 10j to scroll 10
lines down, or 10k to go up by 10 lines.
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
As we discussed in our earlier article, you can use 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'.
10. Less Command – Multiple file paging
Method 1: You can open multiple files by passing the file names as
arguments.
$ less file1 file2
Method 2: While you are viewing file1, use :e to open the file2 as shown
below.
$ less file1
:e file2
Navigation across files: When you opened more than two files ( for e.g –
less * ), use the following keys to navigate between files.
:n – go to the next file.
:p – go to the previous file.