Powering less to highlight syntax and display line numbersSergey Potapov September 23, 2011 #less #syntax-highlight #syntax #unix #linux #bash
Since I am a command line guy I use less tool everywhere and everytime to quickly take a look at files. And quite often those files are different scripts and source code. So, it would be great if syntax was highlighted automatically when I open a file with less. And probably it would be great as well if I saw line numbers.
Making less highlight syntax
It didn't take a long time to find a solution. There is a pretty tool called source-highlight.
It might be exist in standard repository of your system. In Debian like Linux distribution(Debian, Ubuntu, Mint, etc) you can install it with command:
apt-get install source-highlight
It supports a realy big list of languages(in my case 143) and 12 output formats(esc, html, javadoc, latex, etc). You can use man to get closer with it:
source-highlight package provides a little script which receives a source code file and prints highlighted code. Its path is
/usr/share/source-highlight/src-hilite-lesspipe.sh . So we're gonna to use it with less.
Fortunately _less is require flexible tool and we can customize it with number of invironment variables. One of them is
LESSOPEN. A quote from
LESSOPEN Command line to invoke the (optional) input-preprocessor.
So we can you any pipes to prepare an input for less.
Another variable we are going to use is
LESS Options which are passed to less automatically.
We will use
-R option to allow ANSI colors.
So just set up this to variables:
Making less display line numbers
To display line numbers just use
-N option. If you want less to use it everytime add it to
LESS variable as well:
Make it work everytime
To make it work in all shell session just add the next code to the end of you
# syntax highlight for less
Hope this was useful for you. Don't be shy and leave you comments.