Tech Tip: View Config Files Without Comments
I've been using this grep invocation for years to trim comments out of config files. Comments are great but can get in your way if you just want to see the currently running configuration. I've found files hundreds of lines long which had fewer than ten active configuration lines, it's really hard to get an overview of what's going on when you have to wade through hundreds of lines of comments.
$ grep ^[^#] /etc/ntp.conf
The regex ^[^#] matches the first character of any line, as long as that character that is not a #. Because blank lines don't have a first character they're not matched either, resulting in a nice compact output of just the active configuration lines.
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Comments
invert it!
$ grep ^[#] /etc/ntp.conf
Egrep to remove comments and empty lines
egrep -v '^#|^$' /etc/ntp.conf
sed trick
alias cleanconfig='sed -e '\''s/#.*//'\'' -e '\''s/[ ^I]*$//'\'' -e '\''/^$/ d'\'''
I like vim syntax
I like vim syntax highlighting in these cases :)
My version of filtering is
My version of filtering is very similar to the last comment before mine:
egrep -v "^[[:cntrl:] ]*[#;] file
This also filters out comment lines starting with tab(s), followed by # or ; (openvpn's configuration file is a good example that uses both # and ; as the comment characters.)
To make filtering easier, I add the following function into my ~/.bashrc
cf() { [ $# -lt 1 ] && echo "Usage: $0 file" && return; egrep -v "^[[:cntrl:] ]*[#;] $1; }
If I want to view a config file without comment and empty lines, I simply do a
cf config_file
Cheers.
My version of filtering is
Sorry, dropped the part that filters empty lines, here's the corrected one:
egrep -v "^[[:cntrl:] ]*[#;]|^$"
And I found it to be more convenient to define the above command in alias, i.e., I add this line to ~/.bashrc
alias cf='egrep -v "^[[:cntrl:] ]*[#;]|^$"'
Now I can use it in either way of the followings:
I simply do this: $:
I simply do this:
$: "editor" /etc/file_to_view
where "editor" is your favorite editor...then I dynamically filter out the comments using my brain.
come on, this tip is sooo basic - are we going to permute all the possible little CLI tricks one can do and then
compete with one another over who's script is better? - geez.
Testy are we
A bit on the testy side. Get back in the lab, get to work and shut up.
Use 'cut' instead
Better use cut to clear comments from your files. This way you can clear away comments after regular text too. If you want to get rid of extra newlines, you can add a tr.
cut -f1 -d"#" FILENAME | tr -s '\n'
Here's mine
alias jdp='perl -ne "print unless (/^\s*([#!;]|\/\/|$)/);"'
"jdp" == "just data please"
I use this command to strip
I use this command to strip comments from any files I find
grep -vE '(^[[:space:]]*($|(#|!|;|//)))'P.S. I made an alias ;)
This get very similar
This get very similar effect, with less type ;)
$ grep -v '#' /etc/ntp.conf
grep -v '#' file might filter out valid lines
Be careful when you use
grep -v '#' file
as it'll filter lines containing #'s, regardless # is the beginning character of a line or not. In other words, lines like this will be filtered as well:
var1=some_value # define var1
Obviously you don't want that line to be filtered.
I've used that one, too, but it's not as good
It won't strip out blank lines like the regex in the article.
Hi, I also use a lot: $
Hi,
I also use a lot:
$ egrep -v "^[[:space:]]*#|^$" /etc/ntp.confIn case there are spaces in front of the comments.
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