How to hide comments
Introduction
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Although comments can be a blessing in the configuration file of an unfamiliar
system, they eventually become annoying if one is already very familiar with
the file. In some extreme cases, they can actually be an obstruction to
clarity.
Here are two methods for viewing files without hash (#) comments, one for the
command line and one for VIM, and a bit of advice for Debian administrators.
nocomment
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Here is a simple one-line shell script that I have been using for years. I
call it “nocomment”:
egrep -a -v '^[[:space:]]*#' $1 | egrep -a '[[:print:]]'
It can be used as “nocomment file_to_view_clearly” or with a pipe. It filters
out any lines that consist of optional whitespace followed by a ‘#’ character
and any line that does not contain at least one printable character.
Using folds to hide comments in VIM
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VIM has a nice feature called “folding” that allows one to represent blocks of
text with one line or “fold” that can be opened or closed as desired. To learn
lots more about it, type “vim” and then “:help fold.txt”.
Folding can be done manually or automatically with several methods
(indentation, regular expression, syntax, diffs, and markers). The automatic
method based on regular expressions can be used to detect comment lines and
automatically fold them out of the way.
Open a heavily-commented file with vim and do:
:set fde=getline(v:lnum)=~'^\\s*#'?1:getline(prevnonblank(v:lnum))=~'^\\s*#'?1:getline(nextnonblank(v:lnum))=~'^\\s*#'?1:0
Blocks of consecutive comment lines are reduced (folded) to one high-lighted
line that can be opened by moving the cursor to the line and typing “zo” and
closed by typing “zc”. Folding can be globally toggled off and on by typing
“zi”.
I wish to thank everyone who contributed to the thread
http://www.nabble.com/Hide-comments–td17804345.html that I found by searching
Google for ‘ vim “hide comment” ‘, especially Andreas Politz who contributed the
above recipe.
Configuration file examples in Debian
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In many cases, Debian packages come with a set of fully-commented configuration
files typically found in /usr/share/doc/package_name/examples. On initial
installation of the package, these files are copied into /etc to provide a
starting point for configuring the system.
If you have been using Apache or Squid or ISC DHCP or Shorewall or whatever
for many years, consider how much easier to understand your configuration files
would be if all of the comments were removed. In many cases, the entire
configuration file could fit on one screen. You lose nothing: you can always
find the comments again in the examples/ directory. At the limit, you could
replace all of those extraneous comments and examples with just one line:
Hiding comments is good, but getting rid of them completely might be even
better.
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