HTOP is tops in my book

Finally an interactive process viewer
I can really get behind and use.

htop running and showing tree

 On the htop main web site htop describes itself as “an interactive process viewer for Linux”.  Almost every distro of Linux contains the standard process view top, but I have found that htop has been more useful to me as an actual tool instead of just a viewer.

As with other packages, I am a big fan of color when working from the command line.  htop is great because it has several different color schemes that allow me to quickly find things that are important to me while ignoring the other stuff that I am not hunting for.  Just the other day I had a rouge process that was causing me problems and I could not find it.  htop to the rescue, I was able to locate the process that was hanging everything up and two key strokes killed the process and I was on my way.

htop running from a GUI

 htop allows you to set up different meters and graphs so you can quickly review what is going on with the server such as server load, processor load, memory and swap loads.  Another feature of htop is it will allow you to run in tree mode.  The tree mode is great for seeing what processes are spawned or owned by other processes.

Standard view of htop

htop has become a valuable tool for us when monitoring production servers under heavy load.  We have been able to use htop to isolate problems and address them head on.  This package can be installed on RHEL or CentOS using YUM.  Most of my fellow system administrators that work from the command line view htop as great package.  htop will also allow you set up graphs for each of the processors on a multiprocessor machine.  Machines with cores display each core as a separate processor.  When you run htop on a quad, quad core machine it is impressive when the machine is under heavy load.

htop has its home at sourceforge but you will also find a link to htop on our toolkit page.

htop is CodingCREW approved and recommended.

Posted in Uncategorized

Not easily impressed – but wait, MultiTail

In the world of Linux server administration I am not easily impressed, but – once in a while a tool comes along that impresses me so much that I have to talk about it.  One such tool that has risen to the top of my best list is – MultiTail.

MultiTail monitoring 24 log files

MultiTail describes itself as “Tail on Steroids”

Tail on Steroids is putting it mildly!
I would say it should also be looked at as . . .
“Tail for the rest of US”.

Any system administrator that works on production servers knows the value of monitoring logs in real time.  Tail is great for doing just that, but what if you need to monitor two or more logs and/or files in real time to compare information?  You can cobble together several sessions of Tail spanned across multipul monitors but why would you when you can use MultiTailMultiTail will allow you to monitor in real time all the logs and files you want on one monitor.

I have been using MultiTail now for over two months and with each passing day I find new and exciting ways to use this package.   One client has a dedicated server that serves httpd on three production web sites.  These three web sites generate a lot of traffic and we use MultiTail to monitor the access_log and error_log  in real time on each domain looking for patterns of hacking, attacking and DoS.  Certian attackers generate repeatable and/or predictable errors that we can filter for and monitor in real time.

Typical MultiTail Session - Click on image to see full picture - image courtesy of

One of the more interesting features of MultiTail is that you can use Regex to filter your monitoring which allows the user to better focus on what is being monitored while discarding noise and data pollution that is not relevent to the search.

Another cool feature is the ability to use color to differentiat between different monitored expressions, files, stings, etc.  For a person like myself I find that when I am working from the command line, if everything is in black and white I come down with a sever of ADD (Attention Deficate Disorder) real fast.  Color helps me define what I am looking for and helps to break up the monotany of a monochrome enviroment.  Command line, you might ask, who uses the command line, well I hate to say it, yes while I have  a GUI, I still use the command line 80% of the time.

The list of features that MultiTail has are exhaustive, too many to list here, but if you wish to review the list of features we have a link – FEATURES

MultiTail monitoring 4 logs at the same time.

For those of you using RHEL or CentOS you can install MultiTail from the command line with YUM.  Just type yum install multitail.  CentOS will install MultiTail Version 5.2.6 – the latest avaliable.

So in closing for Linux System Admins, Code Heads and others wanting to monitor files and logs in real time we cannot recommend any better solution than MultiTail.  For those of you who are on the MS Windows platform and wish to experiment with MultiTail you can use Cygwin which will allow you to run UNIX/Linux programs on Microsoft Windows.

The CodingCREW tool box has links to MultiTail along with many of the other tools we use and recommend.  MultiTail should be in every system administrators arsenel of tools.
Posted in Uncategorized