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.

  • serverfault.com/questions/21048/…
    – hayalci
    Commented Jul 4, 2009 at 15:29
  • hayalci: that question is for generic tools, this one only for open source
    – sucuri
    Commented Jul 5, 2009 at 12:09
  • @sucuri: most of the "generic" tools are also FLOSS [I should add "fortunately" somewhere :) ]
    – hayalci
    Commented Jul 6, 2009 at 23:43

86 Answers 86


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.)

  • +1, but I think PuTTY is fairly famous, at least among the people who would want to use it in the first place.
    – bcat
    Commented Aug 27, 2010 at 3:47
  • if you google putty, you don't get to silly putty's website until the second page. Commented Jan 7, 2011 at 20:26
  • the guy said "not very famous" :) Commented Jul 28, 2011 at 20:25
  • This was two year ago. :D
    – Joe
    Commented Jul 29, 2011 at 15:49

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



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.

  • One of the few on the list I hadn't heard of, looks very interesting :) Commented Jul 2, 2009 at 3:03
  • 1
    I love Synergy. One of the first apps I install on most of my machines.
    – Chris_K
    Commented Jul 2, 2009 at 4:31
  • Sounds like x2x and/or x2vnc (but doesn't require the "hijacker" to be running X)
    – Thomas
    Commented Jul 8, 2009 at 9:21
  • I use this every day, I control my Linux laptop from my OS X workstation sitting to the right of it. Invaluable!
    – Josh
    Commented Jan 27, 2010 at 22:07

Nobody mentioned screen yet?

  • 1
    Surely screen qualifies as famous. Commented Jul 29, 2009 at 12:52
  • Dunno, lots of folks seem to know about it but I barely see anyone using it. BTW, another one that is amazingly useful for network/network code testing/debugging and is not very well-known is netcat (nc). Let's you hand-craft messages to send over TCP/UDP, can act as a server to see what exactly that weirdo http (or whatever) client is sending etc.
    – igor
    Commented Jul 31, 2009 at 3:43

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.

  • +1 for UnxUtils. You can find more recent builds of many of the tools scattered all over the net, but if you want a one-stop shop for stable binaries, that is the place to go.
    – Ehtyar
    Commented Jul 1, 2009 at 23:28
  • It's worth noting that xrdp seems to be in a perpetual experimental state, but I love it. You can run the rdp daemon on your linux host and remote to it from windows, and it also has the option to rdp through it to another RDP server on its local network, which I've found very handy. Commented Jul 28, 2011 at 20:47

My favourite open source tool is rsync.

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

  • I use rsync to do hourly backups to an external USB drive. I love the "--link-dest" argument! Commented Jul 1, 2009 at 14:38
  • Oh my goodness, yes. Rsync does things that no other copy utility EVER could- it's virtually bulletproof.
    – SilentW
    Commented Jul 2, 2009 at 17:13
  • Can it be used from Windows without cygwin?
    – Jay R.
    Commented Jul 8, 2009 at 4:56
  • I have not tried it, but sourceforge.net/projects/rsyncwin32
    – user4260
    Commented Jul 10, 2009 at 6:45
  • rsync isn't famous? Commented Jan 1, 2011 at 2:03

No one mentioned git.

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

  • i don't think this qualifies as "not very famous" Commented Jul 2, 2009 at 7:17
  • Famous but not yet very famous IMHO;-) Commented Jul 2, 2009 at 18:56
  • Famous but not widely used, which is unfortunate.
    – jtimberman
    Commented Jul 4, 2009 at 3:48
  • How are we defining not widely used? Some projects using Git (from Git's homepage): Linux Kernel, Perl, Gnome, Ruby on Rails, Android, Wine, Fedora, X.org, VLC, Prototype.
    – Telemachus
    Commented Jul 4, 2009 at 15:14

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.

  • Also added dmg support on their latest beta!
    – LiraNuna
    Commented Jul 5, 2009 at 19:54

FileZilla - available as both a client and server.

  • Agree. I use filezilla over IIS ftp server all the time now. SSL support, individual user home directories, and many other features help it shine.
    – Chris
    Commented Jul 4, 2009 at 6:02

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

  • How did this get a -1? Voted up.
    – Ehtyar
    Commented Jul 1, 2009 at 23:15
  • 2
    I'm guessing because it's probably considered famous? Commented Jul 2, 2009 at 0:04
  • @Wayne Koorts - while FileZilla, Notepad++, PuTTy, KeePass etc. are tools practically no one's ever heard of, right ?
    – Rook
    Commented Jul 2, 2009 at 0:27
  • @Idigas: As I said, I'm only guessing. It was a bad thing to add to the question because there's nothing more subjective than "famous". Commented Jul 2, 2009 at 2:34
  • Isn't saying "hardly needs an introduction" just about the definition of famous?
    – Joseph
    Commented Jul 2, 2009 at 3:36

Wireshark = Network Protocol analyzer.

Kismet = A powerful wireless sniffer.

Tcpdump = The classic sniffer for network monitoring and data acquisition, I use it regularly.

Pound = The Pound program is a reverse proxy, load balancer and HTTPS front-end for Web server(s).

Trac = Project management and bug/issue tracking system. Provides an interface to Subversion and an integrated wiki.

Request Tracker = A free web and email-based bug tracking and trouble ticketing system. Features list, documentation screen shots, and download.

Vmstat = The command vmstat reports information about processes, memory, paging, block IO, traps, and cpu activity.

Iptraf = The iptraf command is interactive colorful IP LAN monitor. It is an ncurses-based IP LAN monitor that generates various network statistics including TCP info, UDP counts, ICMP and OSPF information, Ethernet load info, node stats, IP checksum errors, and others.

mc = Visual shell for Unix-like systems.

Postfixadmin = Postfix Admin is a web based interface used to manage mailboxes, virtual domains and aliases. It also features support for vacation/out-of-the-office messages.

pwgen - Automatic Password generation.

Linuxconf = Linuxconf comes with Mandrake Linux and Red Hat Linux, but is also available for most modern Linux distributions. You've probably encountered this tool before if you use one of these distributions, either as the whole package or in one of its modular components. Multiple interfaces for Linuxconf have been available for years, but now we're up to four: GUI, Web, command-line and ncurses.

Webmin = Webmin comes with, and was recently acquired by, Caldera Linux. This tool is not only available for most modern Linux distributions, it also runs on most major flavors of UNIX and is available in around twenty languages (though some modules are not available in all of the languages). As you might guess, Webmin is purely a web-based application and a heavily modular one at that.

OpenVPN = SSL/TLS based user-space VPN. Supports Linux, Solaris, OpenBSD, FreeBSD, NetBSD, Mac OS X, and Windows 2000/XP.

  • 3
    you should edit this and add some more linebreaks :)
    – Blorgbeard
    Commented Jul 4, 2009 at 9:26
  • You should also add links to the homepages of the utilities. Commented Aug 31, 2009 at 0:51
  • +1 for postfixadmin, tempted to give -1 for webmin :[
    – pauska
    Commented Jul 29, 2011 at 9:53

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.

  • 3
    KeePassX (keepassx.org) 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
    Commented Jul 1, 2009 at 23:25
  • 1
    +1 for keepass its a life saver ... i keep it on dropbox to have it on all my computers and also backup ed up Commented Jul 2, 2009 at 11:02
  • Do you know of a text-only way to get a password out of a keepass database? Commented Aug 12, 2010 at 22:12

Screen. It's the most useful tool ever made. Master it and you can be as unto a god, a creature in all places at once.


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
  • htop is awesome. It replaced top on all of my servers. Commented Jul 1, 2009 at 23:30
  • 2
    +1 FreeMind. I do all my planning with it. Commented Jul 2, 2009 at 3:08
  • while htop is nice for the ability to kill, renice, etc. atop is much better as the replacement for the monitoring part of top Commented Oct 5, 2010 at 22:07

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

  • I am surprised how many people don't know about Nagios!
    – Josh
    Commented Jan 27, 2010 at 22:08

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

  • Upvoting for suggesting something I hadn't heard of, thanks :) Commented Jul 6, 2009 at 14:01

ack - a grep replacement. You'll never grep again :)

  • 3
    Note to debian users: package is called ack-grep. The package ack is a Kanji code converter
    – artifex
    Commented Mar 16, 2010 at 12:12

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.

  • ...but how is it different from process explorer? is it worth me taking a look at it, given I use process explorer a lot?
    – Greg
    Commented Jul 2, 2009 at 9:56
  • Process hacker is awesome. It has shutdown and logoff options, so it can replace task manager, even when XP is setup where crtl+alt+del takes your right to taskmanager. Commented Aug 31, 2009 at 0:54

sudo. I also wrote a similar utility a long time ago (different set of features, lightweight) called Calife.

  • I'm not sure whether sudo qualify as "not famous" but calife surely does AFAIK :)
    – Keltia
    Commented Jul 2, 2009 at 12:42

In the security side, I will recommend

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


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

  • 1
    WinSCP is open source. Commented Aug 31, 2009 at 0:56

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.

  • 1
    Hugely popular in the *nix world, though.
    – squillman
    Commented Jul 1, 2009 at 17:08
  • I use it so my wife can watch MTV and ABC streaming video. They block Canadian IP's at these sites, so I just installed squid on my server in the US, configured it to not use the x-forwarded-by header and voila!
    – Kyle
    Commented Jul 1, 2009 at 18:57

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).

  • 3
    and its absolutely ancient! long live windowmaker!
    – Kyle
    Commented Jul 1, 2009 at 14:11
  • I still prefer FVWM. A beast to configure, but I somehow like it :)
    – Sven
    Commented Jul 1, 2009 at 23:03
  • Young whippersnappers. I knew a bunch of Solaris admins that used twm - for preference. Commented Jul 2, 2009 at 9:43
  • Window Maker was my favorite window manager for several years.
    – jtimberman
    Commented Jul 4, 2009 at 3:50
  • What benefits does it have over other window managers..?
    – dbr
    Commented Jul 5, 2009 at 21:19

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.


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

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.

  • I'm using the Disk Usage Analyzer pre-installed with Ubuntu (Baobab IIRC)
    – Myrrdyn
    Commented Jul 1, 2009 at 17:49
  • Yes, this is what Baobab came from which is a standard "not famous" gnome app. Commented Jul 2, 2009 at 8:01

Ack because it's better than grep:

ack is a tool like grep, aimed at programmers with large trees of heterogeneous source code.

ack is written purely in Perl, and takes advantage of the power of Perl's regular expressions.

I'm also becoming a huge fan of Pandoc:

Pandoc is a Haskell library for converting from one markup format to another, and a command-line tool that uses this library. It can read markdown and (subsets of) reStructuredText, HTML, and LaTeX, and it can write markdown, reStructuredText, HTML, LaTeX, ConTeXt, PDF, RTF, DocBook XML, OpenDocument XML, ODT, GNU Texinfo, MediaWiki markup, groff man pages, and S5 HTML slide shows.

  1. TrueCrypt -- Free open-source disk encryption software for Windows Vista/XP, Mac OS X, and Linux
  2. The PortableApps platform -- the the app base itself is not open source i think
  3. The 7-Zip tool -- as against WinZIP, WinRAR, WinSoManyThings!
  4. JkDefrag -- a disk defragmenter and optimizer for Windows 2000/2003/XP/Vista/2008/X64 with many controls
  5. MPlayer -- a movie player which runs on many systems and over many formats
  6. Firefox -- no one talking about this yet! (yes, its popular)
  7. freeSSHd -- free implementation of the SSH server (SFTPd, SCP, SSHd for windows)
  8. Cygwin -- again surprisingly no mention!

Sprinkle (http://github.com/crafterm/sprinkle/tree/master) - a software provisioning tool.

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


GraphicsMagick - Lesser known alternative to ImageMagick, built as a single executable and offers more regular updates.

mod_evasive - Allows Apache to take evasive action when under brute force or Denial of Service attacks.

WikidPad - Excellent personal wiki for storing just about any kind of information.

NcFTP - Command line ftp client and FTP library (LibNcFTP).

cURL - Lesser known alternative to wget (also available as a library - LibcURL).

PdfCreator - Allows you to print documents to PDF on Windows.

DeVeDe - Lesser known alternative to DVDStyler. I like it better because it gives you greater control over disk layout, and automagically creates a menu from the layout.

InfraRecorder - Open Source GUI for cdrtools on Windows.

KiTTY - Lesser known alternative to PuTTY, can be carried on a USB memory stick.

Strawberry Perl - Lesser known alternative to ActivePerl for Windows, comes with a C compiler (MinGW), and has a portable version.

  • Thanks, but are you sure about KiTTY if its open source?
    – Ehsan
    Commented Aug 9, 2010 at 15:31

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