HOWTO: Colour syntax highlighting in nano

[Taoism]

Please note: When I previewed this post, the boards are adding large space gaps into the regular expression examples that have long lines. You will have to remove the gaps for the words that I split by the gaps to be correctly found by the regular expression.

I'm not an uber Linux person, but I did find out about how to add syntax highlighting to files when using nano as an editor in a terminal window, and thought I would add to this forum

nano is an editor you run from inside a terminal window. If you can't get into X or are simply using a terminal and don't want to be bothered with gedit, then nano is an easy, and simple editor to use.

You can add syntax highlighting to certain files you edit in nano in an easy way.

By default the nano documentation is stored in /usr/share/doc/nano:

youngka@quidditch:~
Sat Sep 03 21:01:15 $ cd /
youngka@quidditch:/
Sat Sep 03 21:31:40 $ sudo find -name nano
Password:
./usr/share/doc/nano
./usr/share/nano
./usr/bin/nano
./usr/lib/menu/nano
./bin/nano
youngka@quidditch:/
Sat Sep 03 21:31:59 $

we want a file from a subdirectory of the nano documentation:

Sat Sep 03 21:31:59 $ ls -al /usr/share/doc/nano
total 188
drwxr-xr-x     3 root root  4096 2005-08-23 23:08 .
drwxr-xr-x  1085 root root 28672 2005-09-03 13:54 ..
-rw-r--r--     1 root root  1523 2003-12-29 00:04 AUTHORS
-rw-r--r--     1 root root  3419 2002-07-18 20:08 BUGS.gz
-rw-r--r--     1 root root 10033 2004-11-18 21:38 changelog.Debian.gz
-rw-r--r--     1 root root 53142 2004-06-27 21:36 changelog.gz
-rw-r--r--     1 root root  2179 2004-11-18 21:39 changelog.l10n.gz
-rw-r--r--     1 root root   501 2004-11-18 21:38 copyright
drwxr-xr-x     2 root root  4096 2005-09-03 15:29 examples
-rw-r--r--     1 root root 31246 2004-06-27 21:38 faq.html
-rw-r--r--     1 root root 13136 2004-06-27 21:36 NEWS.gz
-rw-r--r--     1 root root  2354 2003-03-24 07:08 README
-rw-r--r--     1 root root   427 2004-11-18 21:38 README.Debian
-rw-r--r--     1 root root  2870 2003-12-29 00:04 THANKS
-rw-r--r--     1 root root  2032 2003-12-29 00:04 TODO
-rw-r--r--     1 root root  1066 2003-03-24 07:09 UPGRADE
youngka@quidditch:/
Sat Sep 03 21:34:03 $ ls -al /usr/share/doc/nano/examples/
total 16
drwxr-xr-x  2 root root 4096 2005-09-03 15:29 .
drwxr-xr-x  3 root root 4096 2005-08-23 23:08 ..
-rw-r--r--  1 root root 7699 2003-12-27 10:35 nanorc.sample
youngka@quidditch:/
Sat Sep 03 21:34:13 $

To be fair, the nanorc.sample file was actually a .gz file that I extracted by simply typing:

gunzip <filename>

Copy the nanorc.sample file to your home directory and rename it:

youngka@quidditch:/
Sat Sep 03 21:34:27 $ cp /usr/share/doc/nano/examples/nanorc.sample ~
youngka@quidditch:/
Sat Sep 03 21:37:24 $ mv ~/nanorc.sample ~/.nanorc
youngka@quidditch:/
Sat Sep 03 21:38:44 $

In a slightly ironic and amusing (to me at least) twist, I then opened .nanorc in gedit to make my initial edits to the file. Consult the documentation for nano for what all the early stuff in the config file means. What we want is the end of the file.

Near the end of the file are several examples of syntax definitions for different types of files. A simple one to quickly see and verify the colouring works is the xorg.conf syntax definition from a wiki I found:

## syntax highlighting in xorg.conf
##
syntax "xorg" "xorg\.conf$"
color brightwhite "(Section|EndSection|Sub[sS]ection|EndSub[sS]ection)"
# keywords
color yellow "[^A-Za-z0-9](Identifier|Screen|InputDevice|Option|RightOf|LeftOf|Driver|RgbPath|FontPath|ModulePath|Load|VendorName|ModelName|BoardName|BusID|Device|Monitor|DefaultDepth|View[pP]ort|Depth|Virtual|Modes|Mode|DefaultColorDepth|Modeline|\+vsync|\+hsync|HorizSync|VertRefresh)[^A-Za-z0-9]"
# numbers
color magenta "[0-9]"
# strings
color green ""(\\.|[^\"])*""
# comments
color blue "#.*"

Paste it into the end of the .nanorc, and save the file (if in gedit) - no need to close it. Then in a terminal window type:

youngka@quidditch:/
Sat Sep 03 21:37:40 $ nano /etc/X11/xorg.conf
youngka@quidditch:/
Sat Sep 03 21:43:27 $

And you should see the file is colourized for easier editing from within nano! I didn't like the colours the default had. I'm a bit of a throwback to C programming in Borland, so I always set all my editors to show me all comments in green (and italic if possible). So, I went back to the .nanorc file that was still open in gedit and changed the comment color for the xorg.conf syntax file to green (and adjust a couple other colours to look better in my eyes).

I played around with my version of the xorg.conf file to look like this (my terminal is black background with green text by default):

## syntax highlighting in xorg.conf
##
syntax "xorg" "xorg\.conf$"
color brightwhite "(Section|EndSection|Sub[sS]ection|EndSub[sS]ection)"
# keywords
color yellow "[^A-Za-z0-9](Identifier|Screen|InputDevice|Option|RightOf|LeftOf|Driver|RgbPath|FontPath|ModulePath|Load|VendorName|ModelName|BoardName|BusID|Device|Monitor|DefaultDepth|View[pP]ort|Depth|Virtual|Modes|Mode|DefaultColorDepth|Modeline|\+vsync|\+hsync|HorizSync|VertRefresh)[^A-Za-z0-9]"
# numbers
color magenta "[0-9]"
# strings
color white ""(\\.|[^\"])*""
# comments
color green "#.*"

Not much of a change, but a small one, and it is easy to do. If you make a mistake with a regular expression, nano will pause in loading the file you want to edit to alert you to the error.

If you play with the colour definitions and make your own, for file types you prefer, it is important to remember that nano applies the color highlighting in a top-down fashion, from first to last (which is why all the definitions usually put the comment regex as the last line of the syntax section for a given file type.

After playing with nano for a while, I have come up with a syntax definition I would like to share.

First though, I did find another site (wiki) with three definitions listed:
Nano Context Highlighting is a wiki entry on a Gentoo wiki. This is the wiki that I got the xorg.conf syntax definition from.

I decided to try and write my own syntax definition, and one file that I do interact with on occassion in a terminal is the apache configuration file (apache2.conf or httpd.conf).

In the spirit of sharing, here is the syntax file I came up with. I am not saying it is the best that can be done, and I do plan to tweak it more, but here it is none-the-less:

## Apache httpd.conf highlighting
##
#how to add sites-enabled files?  "default" is too generic to keep in here I think
syntax "Apache2" "apache2\.conf$" "httpd\.conf$" "default"

# for reference... I don't want to keep scrolling back up ;)
## Legal colors: white, black, red, blue, green, yellow, magenta, cyan.
## You may use the prefix "bright" to mean a stronger color highlight.

# Apache Directives?
color brightwhite "(ServerRoot|(Lock|Pid)File|Timeout|(Max)?KeepAlive(Requests|Timeout)?)"
color brightwhite "(User|Group|LogFormat|ErrorLog|Include|(Script)?Alias)"
color brightwhite "(ErrorDocument|AccessFileName|UseCanonicalName|TypesConfig|DefaultType)"
color brightwhite "(HostnameLookups|IndexOptions|(Readme|Header)Name|LanguagePriority)"
color brightwhite "(AddIcon(ByEncoding|ByType)?|DefaultIcon|IndexIgnore|BrowserMatch)"
color brightwhite "(Add(Encoding|Language|(Default)?Charset|Type|Handler)|DirectoryIndex)"
color brightwhite "(DocumentRoot|Server(Admin|Signature)|LogLevel|CustomLog)"
color brightwhite "((Force)?LanguagePriority|NameVirtualHost)"

# These are all config tokens that appear inside module/directory brackets
color yellow "(SetHandler|Order|Deny|Allow|SetOutputFilter|AllowOverride|FileInfo|AuthConfig|Limit)"
color yellow "([^A-Z0-9a-z]Options|Indexes|(\+|\-)?SymLinksIfOwnerMatch|Includes(NoExec)?|(\+|\-)?MultiViews)"
color yellow "(None|allow,deny|deny,allow|(allow)? from (all)?|Prefer|Fallback)"
color yellow "(Add(Handler|OutputFilter)|NumServers|AcceptMutex)"
color yellow "((Min|Max)Spare(Threads|Servers)|Start(Threads|Servers))"
color yellow "(MaxClients|(Max)?ThreadsPerChild|MaxRequestsPerChild)"
color yellow "(FancyIndexing|VersionSort|ExecCGI|FollowSymLinks)"

# Highlight boolean toggles (i.e. KeepAlive On)
color brightred "(On|Off)[[:space:]]*$"

#log levels
color brightred "[[:space:]]+(debug|info|notice|warn|error|crit|alert|emerg)[[:space:]]*$"
color brightred "[[:space:]]+(combined|common|referer|agent)[[:space:]]*$"

#BrowserMatch directives
color brightred "[[:space:]]+(redirect\-carefully|nokeepalive)[[:space:]]*"
color brightred "[[:space:]]+(force\-response\-1\.0)[[:space:]]*"
color brightred "[[:space:]]+(downgrade\-1\.0)[[:space:]]*"

#AddType application params
color brightred "[[:space:]]+application/[a-zA-Z\-]+[[:space:]]*"

#AddHandler param
color brightred "[[:space:]]+type-map[[:space:]]*"

# Numbers 
color magenta "[[:space:]]+[0-9]+[[:space:]]*"

# IP Addresses
color magenta "(/)?(2[0-5]{2}|1[0-9]{2}|[1-9][0-9]|[1-9])(\.(2[0-5]{2}|1[0-9]{2}|[1-9][0-9]|[0-9])){3}([[:space:]]+::(2[0-5]{2}|1[0-9]{2}|[1-9][0-9]|[0-9])/(2[0-5]{2}|1[0-9]{2}|[1-9][0-9]|[0-9]))?"

# Stolen from the HTML example further up this file
color brightcyan start="<" end=">"

# strings
color white ""(\\.|[^\"])*""

# Unix-based paths
# can't use \] in the regex for some reason?!? Maybe a bug?
# this is preventing a 100% "to the end of the line" match for a few
# lines (the trailing characters from ] to the EOL are not highlighted.
# if anyone knows how to make it work, let me know.. ;)
color white "[[:space:]]+(/[/\[\^#A-Za-z0-9\.\*\_\-]+)+"

# Comments - match 0 or more spaces/tabs preceding the comment
color green "^[[:space:]]*#.*"

One thing I did notice is that capture-suppression in regular expressions does not work in nano - i.e. I tried something like (?:KeepAlive )(On|Off) and the ?: kept resulting in errors. I think there is also a (maybe) a bug with the right square bracket not being able to be escaped in a class definition : [\[] will work, but [\]] throws an error.

If anyone else has some sybtax definitions for nano they could share, please add them to this thread!

Here is one more I found for the road (don't remember where, sorry):

## Here is an example for shell scripts
##
 syntax "shellscript" "\.sh$" ".bashrc"
 color brightgreen "^[a-zA-Z_0-9]+\(\)"

 color brightwhite "\<(case|do|done|elif|else|esac|exit|fi|for|function|if|in|local|read)\>"
 color brightwhite "\<(return|select|shift|then|time|until|while)\>"
 color brightwhite "(\{|\}|\(|\)|\;|\]|\[|`|\\|\$|<|>|!|=|&|\|)"
 color brightwhite "-(e|d|f|r|g|u|w|x|L)\>"
 color brightwhite "-(eq|ne|gt|lt|ge|le|s|n|z)\>"
 
 # commands
 color brightblue "\<make\>" 
 color brightblue "\<(alias|cat|cd|chmod|chown|cp|echo|env|eval|export|grep|install|let|ln|ls)\>"
 color brightblue "\<(mkdir|mv|rm|sed|set|tar|touch|umask|unset)\>"
 # a program I installed
 color magenta "(figlet)"
 # variables?
 color brightred "\$\{?[a-zA-Z_0-9]+\}?"
 # strings?
 color brightyellow ""(\\.|[^\"])*"" "'(\\.|[^'])*'"
 # comments
 color green "#.*$"

Thanks for reading and I hope you found this at least interesting, if not useful!

Cheers,
Keith.

[Taoism]

I did a syntax for highlighting a Conky (.conkyrc) file:

## Conky config highlighting
## 
syntax "Conky" ".conkyrc$"

# keywords
color brightblue "(use_spacer|background|use_xft|xftfont|xftalpha)" 
color brightblue "(mail_spool|update_interval|own_window)"
color brightblue "(double_buffer|minimum_size)"
color brightblue "(draw_(outline|borders|shades)|stippled_borders)"
color brightblue "border_(margin|width)"
color brightblue "default_((shade_|outline_)?color)"
color brightblue "(alignment|gap_x|gap_y|no_buffers|uppercase)"
color brightblue "^TEXT[[:space:]]*$"

# Highlight boolean toggles
color brightred "[[:space:]]+(yes|no)[[:space:]]*"

# Conky position descriptors
color brightred "(top_left|top_right|bottom_left|bottom_right)[[:space:]]*$"

# Numbers 
color magenta "[[:space:]]+([[:space:]]*([0-9]\.?))+[[:space:]]*"

# variables
color brightred "\$\{?[a-zA-Z_0-9\# ]+\}?"

# Comments - match 0 or more spaces/tabs preceding the comment
# back assertions don't seem to work, so we have to assume that all
# comments will start on a new line (otherwise the RGB colour codes
# will cause their lines to get treated as comments
color green "^[[:space:]]*#.*"

# apply after comments (it's just easier)
# colour codes
color white "[[:space:]]+\#[0-9A-Fa-f]{6}"

Cheers,
Keith.

[Xk2c]

Have a look here :

http://forums.gentoo.org/viewtopic.p...382452#1382452




Have Fun..

[Taoism]

Cool stuff! I posted my syntax defs onto that thread, and borrowed a few for myself! Thanks for pointing it out to me!

Cheers,
Keith.

[Xk2c]

Your are welcome.

[xmux]

Hey i did this how to but something i did wrong and now my nano doesnt work!! How can i get it back?? i tried already sudo apt-get remove nano and apt-get install nano but it doesnt work!!

When it runs on terminal the letters looks like UFO alphabet!! Can someone help me??

[xmux]

youngka@quidditch:/
Sat Sep 03 21:34:27 $ cp /usr/share/doc/nano/examples/nanorc.sample ~
youngka@quidditch:/
Sat Sep 03 21:37:24 $ mv ~/nanorc.sample ~/.nanorc
youngka@quidditch:/
Sat Sep 03 21:38:44 $

I think in this time it happend!!
you can see it also

What should i do???

thanks

[xmux]

hey thanks, me idiot i wrote some false things!! now i got it back again thanks anyway!! I moved the nanorc to somewhere which doesnt exist...

thanks anyway!!

[tennvolsmb]

ok im having the same problem but i dont know how to fix it please someone help!!!

[qasimlone]

I have followed all the steps. It still does not show the colours. How ever if i add errors to nanorc file. Nano gives me error before starting. It means that it is reading the file before starting but its not working