Nano syntax highlighting: catch-all syntax for configuration files

Question

After years of using nano, I only recently learned that it supports syntax coloring... (Why would they turn that off by default? ) Well, I thought I'll make up for it by making extra good use of it from now on...
Unfortunately it didn't ship a highlighting syntax for the the kind of files that I use nano the most for: system configuration files.
So I wrote my own, and after tweaking a bit here and there whenever I encountered a config file for which the highlighting wasn't satisfactory at first, I think the result is now good enough (screenshots below) that it's worth sharing with my fellow Arch users:
Code & Instructions:
Here is the syntax definition:
# config file highlighting
syntax "conf" "(\.(conf|config|cfg|cnf|rc|lst|list|defs|ini|desktop|mime|types|preset|cache|seat|service|htaccess)$|(^|/)(\w*crontab|mirrorlist|group|hosts|passwd|rpc|netconfig|shadow|fstab|inittab|inputrc|protocols|sudoers)$|conf.d/|.config/)"
# default text
color magenta "^.*$"
# special values
icolor brightblue "(^|\s|=)(default|true|false|on|off|yes|no)(\s|$)"
# keys
icolor cyan "^\s*(set\s+)?[A-Z0-9_\/\.\%\@+-]+\s*([:]|\>)"
# commands
color blue "^\s*set\s+\<"
# punctuation
color blue "[.]"
# numbers
color red "(^|\s|[[/:|<>(){}=,]|\])[-+]?[0-9](\.?[0-9])*%?($|\>)"
# keys
icolor cyan "^\s*(\$if )?([A-Z0-9_\/\.\%\@+-]|\s)+="
# punctuation
color blue "/"
color brightwhite "(\]|[()<>[{},;:=])"
color brightwhite "(^|\[|\{|\:)\s*-(\s|$)"
# section headings
icolor brightyellow "^\s*(\[([A-Z0-9_\.-]|\s)+\])+\s*$"
color brightcyan "^\s*((Sub)?Section\s*(=|\>)|End(Sub)?Section\s*$)"
color brightcyan "^\s*\$(end)?if(\s|$)"
# URLs
icolor green "\b(([A-Z]+://|www[.])[A-Z0-9/:#?&$=_\.\-]+)(\b|$| )"
# XML-like tags
icolor brightcyan "</?\w+((\s*\w+\s*=)?\s*("[^"]*"|'[^']*'|!?[A-Z0-9_:/]))*(\s*/)?>"
# strings
color yellow "\"(\\.|[^"])*\"" "'(\\.|[^'])*'"
# comments
color white "#.*$"
color blue "^\s*##.*$"
color white "^;.*$"
color white start="<!--" end="-->"
To install, save the above above code snippet as a file called conf.nanorc in the folder /usr/share/nano/ (or /usr/local/share/nano/ or similar if you feel strongly about the /usr <--> /usr/local separation), and then add the following to the end of the file /etc/nanorc:
## Configuration files (catch-all syntax)
include "/usr/share/nano/conf.nanorc"
Hints:
The colors I chose look good (imo) with the terminal background and color settings that I use, but might not look good, or even readable, with yours, so simply change the color names in the code snippet to whatever you prefer - valid color names are:
If you use a console with white background, you'll have to change at least the white color I chose for comments and punctuation.
The first code line in the snippet includes a regular expression that defines for which file names this syntax highlighting should be used. Whenever you encounter a config file that is not matched by this, but you would still like to open it with syntax highlighting, you can manually select this syntax with nano's -Y switch, like so:
nano -Y conf myConfigFile
Technical Note:
It's implemented as a single catch-all syntax, since nano chooses which syntax to apply based on the filename, and in the case of config files usually not much can be learned about the content format from the file name extension (.conf can by anything from flat key/value tuples to XML, .ini can be the official INI format or something else, etc...).
This means that some compromises have been made, so with this highlighting syntax probably no config file looks 100% as good as a highlighting syntax that would be specifically optimized for one kind of config format, but all in all the vast majority of config files should look pretty good.
Screenshots:
/etc/rc.conf,  /etc/hosts:
/etc/pacman.conf,  /etc/group:
xorg.conf,  some .desktop file:
httpd.conf (Apache config),  php.ini:
More screenshots:
/etc/fonts/fonts.conf (uses XML)
/etc/inittab
/etc/fstab
/etc/inputrc
/etc/mime.types
/etc/protocols
/etc/xinetd.conf
See Also:
nano syntax highlighting: GNU makefiles
Update [2012-01-28]: Made some more improvements to the syntax definition (see post)
Last edited by sas (2012-02-01 15:26:43)

Answer 1

doug piston wrote:I deal with alot of .mk files and would love to see it there.
You mean GNU makefiles?
I'm afraid they might be out of scope for this generic config-file syntax.
Logically they're not system config files, and technically they're a pretty specialized and complex format (different "types" of rules, rules spanning multiple lines, rules containing arbitrary Bash code, etc.).
This is how an .mk file currently looks with this highlighting syntax:
$ nano -Y conf /usr/lib/httpd/build/rules.mk
And apart from highlighting variables of the form $$abc or $(abc), I'm not sure how much can be improved here without breaking the highlighting for more conventional config files.
It would probably be better to create a specialized highlighting syntax just for .mk files.
EDIT: I sat down and did just that, here's the result: nano syntax highlighting: GNU makefiles, and here is how the above makefile snipped looks with it:
Last edited by sas (2012-02-01 15:18:52)