less is used to display contents of a file, as well as allow navigation. Its name is derived from being the opposite of
$ less file.txt These are the contents of "file.txt". The output will actually take up the entire screen, and you can navigate using Vim-like commands.
Useful Options / Examples
Navigation/ General Commands
less can be navigated using Vim-like commands.
k: move to the next/ previous line of the file
b: move to the next/ previous page of the file
h: displays a help screen with a summary of
For more commands, use
man less or visit this tutorial page.
?def (“**” represents highlighted text)
**def** foo(): print "foo" **def** bar(): print "bar" **def** main(): foo() bar()
less, you can type
/<regex> to search forward for a regular expression. You can use
n to find the next occurrence, or
N to find the previous occurrence.
?<regex> is the same, but searches backwards and inverts
m <lowercase letter>,
' <lowercase letter>
m command inside
less allows you to “mark” the current line at the top of your screen with that letter. Later, you can use the
' command with that same letter to jump back to that position.
less -N huge_file.txt,
less --LINE-NUMBERS huge_file.txt
1 These are the contents of "huge_file.txt". 2 3 You can't really tell from here, but this file goes on and on and on and 3 on... 4 5 You can navigate this huge file using Vim-like commands! 6 7 If it's hard to keep track of where you are in the file though... 8 9 Use -N or --LINE-NUMBERS to help you out!
--LINE-NUMBERS flags turn on line numbers on the side. You can also use
--line-numbers to suppress line numbers.
less +F log.txt
echo "hello world!" >> log.txt
... Line 41 Line 42 Line 43 Line 44 Line 45 Line 46 Line 47 Line 48 Line 49 Waiting for data... (interrupt to abort)
+F flag sets
less to work in “follow mode”, which tracks additions to a file. For example, when you use the
>> operator to append to a file,
less will automatically track it and display what you appended. This is especially useful for error logs on a server, for example. You can press
Ctrl-c at any time to stop following and navigate normally, and then
F to continue following the file.