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Posts tagged search
Stop Vim from Highlighting Search Results
Jul 14th
You can search to words in vim using the ‘/’ key when you’re in command mode. Unfortunately, new admins in their desperation to find a word may inadvertently specify a term too generic.
Vim provides search highlighting, but sometimes, the results are just plain fugly. For example, when searching for the word module in a httpd.conf file, this is what could happen:
Vim showing Highlights
Yeah, not really the the most visually pleasing. To temporarily turn of highlighting, just type
:nohlsearch
in vim command mode.
The next time you search for something, or press the ‘n’ key, it will be automatically turned back on.
2 CLI ways to determine which rpm package has a program you wish to install in Fedora Linux
Jul 8th
There are 2 ways I know of to search for a particular program to install in Linux. As usual, I’ll be focusing on the Command Line Interface (CLI).
So, you’ve heard about the versatile port scanning tool called nmap and want to install it in Fedora Linux. The only problem is, you don’t know if it has been pre-packaged and is available as an rpm binary. No worries, all you need to do is search for using yum.
Use the yum search command.
yum search nmap
Based on its output, you know there are packages available, and all you need to do is yum install nmap
[raja@atreides ~]$ yum search nmap Loaded plugins: fastestmirror, presto, refresh-packagekit ================================ Matched: nmap ================================= nmap.i586 : Network exploration tool and security scanner nmap-frontend.i586 : the GTK+ frontend for nmap onesixtyone.i586 : An efficient SNMP scanner perl-Nmap-Parser.noarch : Parse nmap scan data with perl psad.i586 : Port Scan Attack Detector (psad) watches for suspect traffic
Or, you might know that its called nmap, and want to search through you yum repositories to find if any of the available rpms have a file called nmap. To do that, use the yum provides */
yum provides */nmap
Look at what it gives:
[raja@atreides ~]$ yum provides */nmap Loaded plugins: fastestmirror, presto, refresh-packagekit 2:nmap-4.76-4.fc11.i586 : Network exploration tool and security scanner Repo : fedora Matched from: Filename : /usr/share/nmap Filename : /usr/bin/nmap
From this, you know that the nmap-4.76-4.fc11.i586 rpm contains these files, and by installing it, you get nmap.
How to search and replace in Vim
Jun 25th
Just for reference, may help other people. Searching for text and replacing in vim is an invaluable skill, which helps sysadmins during the conf. file troubleshooting.
For example, assume you have this /etc/hosts file with a list of machines that are numbered sequentially. For some insane reason, some dude suggests a now naming scheme. Replacing 10 or 15 lines manually is a pain, not to mention error prone.
192.168.0.1 node01 192.168.0.2 node02 192.168.0.3 node03 192.168.0.4 node04 192.168.0.5 node05 192.168.0.6 node06
Now, your resident office genius decides that the names for these machines should be cluster-nodexx instead of nodexx. Great, now imagine having 200 machines in your hosts file. No way you’re going to manually edit that by hand. This is where vim’s search & replace function comes in handy.
First, open the file in vim:
# vim hosts
Now, to replace the the word node with cluster-node, press the colon “:” to enter command mode an type the following:-
:%s/node/cluster-node/gc
Lets break down the command.
- %s : instructs vim to search
- /node/: The words within the first two forward slashes are the characters vim will search for
- /cluster-node/: The words between the second and third forward slashes are what vim will replace node with.
- g: after the thrid forward slash, the ‘g’ stands for global. Without this, vim will only replace the first occurrence of the word node.
- c: ‘C’ will make vim prompt you for confirmation before replacing the word. Very handy especially when editing source or configuration files.
- Here’s an example of how this would look like:
Note the highlighted matches, and the prompt below asking for your confirmation.
This should help you do some mass replacing with ease.
