Syntax highlighting with less, trouble with lexer

I have installed python-pygments and using it for syntax highlighting with less as described by mankoff here I put a function in my .bashrc

cless () {
    pygmentize -f terminal "$1" | less -R
}

it is enabling syntax highlighting with less. But when I am going to open a file like /etc/fstab or /etc/apt/apt.conf a error saying

Error: no lexer for filename '/etc/apt/apt.conf' found

I found option to show pygmentize the lexer with -l at this manpage. But what will be the appropriate lexer for such files? and how to use it?

Buried in pygmentize --help:

If -g is passed, attempt to guess the lexer from the file contents, or pass through as plain text if this fails (this can work for stdin).

Simply change your code to:

cless () {
    pygmentize -gf terminal "$1" | less -R
}

To have syntax highlight on Ubuntu/Debian first install

apt install source-highlight

Then you may want to add this two environment variables to ~/.bashrc

export LESSOPEN="| /usr/bin/src-hilite-lesspipe.sh %s"
export LESS=' -R '

Tip: Also notice v on less open the file on default editor (defined by select-editor command) that maybe have syntax highlight. Here it is how to add compatibility to a lot of file types in nano.

Reference

• gnu.org - 2.7 Using source-highlight with less
• bash - less command and syntax highlighting - Unix & Linux Stack Exchange
• How to syntax highlight via Less - Super User