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I believe every system administrator is used to open source by now. From Apache to Firefox or Linux, everyone uses it at least a little bit.

However, most open source developers are not good in marketing, so I know that there are hundreds of very good tools out there that very few people know.

To fill this gap, share your favorite open source tool that you use in your day-to-day work.

*I will post mine in the comments.


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86 Answers 86

UnxUtils: This is a port of various gnu shell utilities based on msvcrt.dll so it understands native windows paths - i.e. you don't need to map to a /cygdrive path. This is a key advantage over Cygwin if you have to interact with native windows commands or homebrew CL utilities.

Strings: is a very good way to scrounge through files for items of text. Many, many uses.

Flex: Really designed for writing lexical analysers, with a little bodge artistry and a C compiler it can be used as an uber-grep. I don't use it all that often but it can come in surprisingly handy in that role.

Fetchmail and Procmail: Core of my email system for well over a decade, since I had dial-up internet connectivity. If it ain't broke ...

rdesktop: an open source RDP (terminal services) client that works surprisingly well.

PythonWin:, particularly as packaged in Activestate Python. Python on Windows works a lot better than you might think. When used with COM Makepy it's really good for scripting COM APIs.

Wget: an exceedingly useful FTP/HTTP downloading tool.

Leafnode: if you still read any of the newsgroups that still have decent active traffic this is quite a good way to do it. Again, a bit of legacy from my dialup days but it still gets used on occasion.

Abiword and Gnumeric: full featured wordprocessing and spreadsheet software that's far leaner and meaner than OpenOffice.

Xfig: Visio type diagramming tool with an odd user interface. Once you get used to the paradigm it's much easier on my poor old mouse hand than a modern direct maniulation interface. Worth a mention for the ergonomics.

Tcl/Tk: Overshadowed by Perl and Python, Tcl is very easy to embed C code into - it was designed specifically for embedding. Surprisingly useful nonetheless, and the Tk toolkit is very easy to whip up a GUI with. Modern versions support theming so your applications no longer have to look like Motif.

Ghostscript: One of the great unsung heroes of the open-source world. A free postscript interpreter with a whole ecosystem of derived items - PS and PDF viewers, PDF creation tools, printer RIPs and all sorts of Postscript conversion tools. Perhaps most widely used outside open-source circles (if not actively credited) in its role in the back-end of PDFCreator

That's just a sampling of the obscure stuff without mentioning Vim, LaTeX, Firefox, python, gcc, gtk & qt and the Berkeley TCP stack - to name but a few.


My favorite app is the Window Maker, a very lean and fast Linux window manager (similar to KDE, Gnome, etc).

It is not very famous, but available for most distros (on Ubuntu, do apt-get install wmaker).

and its absolutely ancient! long live windowmaker! – Kyle Hodgson Jul 1 '09 at 14:11

I have been finding that many people don't yet know about Process Hacker. It's on par with Sysinternals' Process Explorer.

Edit in response to Greg's comment:
Sorry for the delay in responding... It also has 2 tabs that show services and TCP/UDP connection info which I think is really nice. You can get the same info in the services tab in Process Eplorer when sorted by tree view, but then you lose the ability sort within the services list.


I'm a big fan of Filelight. I never knew determining data usage on my hard drive could be so easy or look so pretty.


The Apache Foundation's ActiveMQ.

I replaced a commercial MQ with it two years ago. It is blazing fast, has lots of HA capabilities and an excellent features list. It is not always easy to configure, but the licensing on the commercial one was starting to look like a pretty decent salary. Time to go open source!


My favourite open source tool is rsync.

I use it almost every day and it is still not as famous as it should be:-)


Zim Desktop Wiki

Small desktop wiki that works on Linux as well as Windows and OSX.

I use it to keep my tasks organized as well as to document things as I go before putting them into the company wiki.


I have to say Squid. I dont think its all that popular, at least not in the Windows world. We use it for many different things: content filter and port blocker included.

Hugely popular in the *nix world, though. – squillman Jul 1 '09 at 17:08

No one mentioned git.

It is not as well known as cvs or svn but I think it will be one day.


I'm afraid that mine are all not very famous and minimalistic, but I live happier since I use them:

Sup - mutt-like console e-mail written in Ruby

wmii - minimalist window manager controlled by a filesystem exported with 9P

Vimperator - firefox plugin to provide a vim-like web brower

MCabber - console mode jabber client

pwsafe - command-line password keeper

AfterGlow - graph-generation from CSV files (for security visualization)

tcptraceroute - traceroute implementation using TCP packets.

pdftk - If PDF is electronic paper, then pdftk is an electronic stapler-remover, hole-punch, binder, secret-decoder-ring, and X-Ray-glasses.

imapfilter - Delete, copy, move, flag, etc. messages residing in mailboxes at the same or different mail servers


leo - invaluable outliner for data organizing.


I use many that I couldn't work without but that I don't consider "not very famous" (openssh, openvnp, apache, rsync, ...). Two very useful little utilities that many may not have heard of sprint to mind:

  • Pipe Viewer (pv): keep tabs on long operations
  • htop: a prettier alternative to top with a few useful extra features as well as the pretty

Both can generally be found in standard repositories (they are both in Debian Etch and above) and are relatively painless to compile if your distro doesn't have them.

Edit: another excellent tool that isn't very well known in my experience:

  • FreeMind: a very useful "mind map" style note recording/arranging app
+1 FreeMind. I do all my planning with it. – David Mackintosh Jul 2 '09 at 3:08

KeePass is a free open source password manager, which helps you to manage your passwords in a secure way. You can put all your passwords in one database, which is locked with one master key and/or a key file.

KeePassX ( is a cross platform (which makes it twice as valuable as KeePass IMO) fully compatible KeePass alternative with a similar interface, written in c++. – Ehtyar Jul 1 '09 at 23:25
+1 for keepass its a life saver ... i keep it on dropbox to have it on all my computers and also backup ed up – Gabriel Solomon Jul 2 '09 at 11:02

In the security side, I will recommend

Both are well known in the security community, but not very much outside of it.


I love PuTTY !

The PuTTY executables and source code are distributed under the MIT licence, which is similar in effect to the BSD licence. (This licence is Open Source certified and complies with the Debian Free Software Guidelines.)


I love CFengine for automatic configuration management on my Debian boxes.

An example on how to edit sysctl.conf.


Sprinkle ( - a software provisioning tool.

It is easier than Puppet or Chef, but very powerful. And it is Ruby based, recipes are Ruby scripts.


I'm a huge Puppet fanboy myself, and Systemimager has made my life SIGNIFICANTLY less hateful since I started with it ~2 years ago. iperf is a nifty bandwidth-assessment/troubleshooting tool, and of course the venerable tcpdump!

Consider providing a link. – Jordan S. Jones Jul 4 '09 at 15:03

Notepad++ lightweight, has excellent support for different formats, my main text editing tool in windows.


FileZilla - available as both a client and server.


Vim/gVim - an editor practically no one's heard of!

I'm guessing because it's probably considered famous? – Wayne Koorts Jul 2 '09 at 0:04

WinSCP, although I'm not completely sure that's Open Source. If not, it's a toss up between Mailcleaner and HylaFAX.

WinSCP is open source. – Justin Dearing Aug 31 '09 at 0:56

My favourites that haven't been mentioned yet:

  • WinMerge: Directory and file merge / diff tool.
  • jEdit: Text editor.

And of course all of the unsung heroes of the *nix command-line world like grep, bash and of course man.


Can you consider a webserver as a tool? If so, nginx has my vote. Else, I would vote for ttcp for throughput testing.

I also find that not a lot of people use xargs. For example, here's a good one I just figured out: how to shred files that have spaces in the filename using find, xargs and shred.

 find . -type f -print0 | xargs -0 shred -u -v


Synergy lets you easily share a single mouse and keyboard between multiple computers with different operating systems without special hardware. It's intended for users with multiple computers on their desk since each system uses its own display.

It is also platform independent.

I love Synergy. One of the first apps I install on most of my machines. – Chris_K Jul 2 '09 at 4:31

Saxon for XSLT 2.0 and XQuery 1.0 work


dstat - imagine vmstat, iostat, top, ps, as well as apache, mysql, etc. all able to output metrics on the same line at the same interval. cross-referencing app-level metrics with system-level metrics is huge.

siege - better than any other URL hammering tool out there

squid - layer 7 routing and caching, quick and easy

maatkit - MySQL is not the same without it

MySQL Proxy - the example lua scripts are enough to make MySQL snooping painless


Nagios--Comprehensive IT infrastructure monitoring ensures you can resolve problems before they affect critical business processes....


7-zip--a file archiver with the high compression ratio. The program supports 7z, ZIP, CAB, RAR, ARJ, LZH, CHM, GZIP, BZIP2, Z, TAR, CPIO, ISO, MSI, WIM, NSIS, RPM and DEB formats.


PhpMyAdmin--a tool written in PHP intended to handle the administration of MySQL over the Web. Currently it can create and drop databases, create/drop/alter tables, delete/edit/add fields, execute any SQL statement, manage keys on fields.


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