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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

To complete the list I like to add monit: lightweight and easy to configure monitoring and automated error recovery daemon. Less complex than Nagios and bb4, but far more easy to configure.

config for sshd: (copied from monit website)

check process sshd with pidfile /var/run/
start program  "/etc/init.d/sshd start"
stop program  "/etc/init.d/sshd stop"
if failed port 22 protocol ssh then restart
if 5 restarts within 5 cycles then timeout

I like the terminal tools
Yakuake .. its a Quake-style terminal emulator based on KDE Konsole technology.
Terminator .. Its a terminal emulator with many cool features like

auto safe session, screen split,find function and many many more.
enjoy it :)


In addition to the numerous good answers already submitted, I'd like to add:

ccrypt: an implementation of AES (Rijndael) for file encryption/decryption

SAGE: a mathematical software suite (which bundles the following two packages)

MPFR: a C library for arbitrary-precision computation

PARI/GP: a C library and command-line calculator for number theory and related applications

GnuPG: e-mail encryption/decryption/authentication software (regrettably, too little used)


I like PgBouncer. It's a connection pooling daemon for Postgresql.


mtr - My Traceroute, included with most Linux distros but I keep running into folks who haven't heard about it. It's a traceroute/ping mashup, checking every hop of a traceroute continuously and giving you real time stats. You can spot packet-dropping routers and high-latency connections within seconds.


I would have to say Valgrind. As a developer it's extremely useful for realtime debugging of memory problems among others. But it seems no one has yet mentioned it so that means it really isn't that famous in the IT community at large. Maybe just linux/unix developers know about it.

Another one that is also not mentioned but is in the same category is gdb.

No has mentioned gcc either that I can see.

Or gnu make for that matter. I'm sure many of you out there use it all the time but give it no thought.


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

Many tools that I am using on a daily basis were already mentioned. bwm-ng anyone ? It is little live bandwidth monitor.


My favorites that haven't been mentioned:

  • twidge - update a twitter account via command line
  • fbcmd - update a facebook account via command line
  • winexe - execute command on a Windows box
  • ts (task spooler) - maintains a queue of commands and executes them one by one, commands can be added to queue at any time
  • qrand - download random numbers from QRBG website
  • adito - SSL VPN, extremely useful
  • ajaxplorer - web-based file manager
  • lld2d - allow linux-based router to respond to windows LLTD requests

and finally

  • lspci - this has to be the best tool for finding out exactly what hardware is in your system

MindTouch. It's developers are actually picked up a lot of steam and thus stands apart from the generalization that "most open source developers are not good in marketing."

Big things happenin'!


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!


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


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.


nc: Along with dd it can do wonders in data transfers. We can cloned harddisks/partitions piping nc, gzip and dd together.

dvdisaster: It is really nice tool to create error correction code of CD/DVDs. The ecc occupies much less space then actual disk and even when both ecc and original disk are corrupted (a little) we can still get original data back.

htop: It is way cooler then top as it uses ncurses to show things in nice colors and supports mouse.

tcptrack: It can be used to see live tcp sessions as th4y are getting created and closed. It can sort connections by speed. So you can see where is most of the bandwidth going.

iptraf: It can be used to monitor lot of network interfaces at once to see how much they are being used.

fdupes: It can help in finding duplicate files.

mail-notification: It gives nice pop-up with sound near notification area when new email comes to any of the configured accounts.

kompare: It can give visual diff of two files. You will have to use it once on two similar text files to really understand what I mean by visual diff. My favorite is to compare zone files of primary and secondary DNS to ensure they are consistent.

convert: It is very useful in converting from one image type to another. Specially to eps for Latex documents.

dos2unix / unix2dos: These help in changing files ending with '\r\n' to '\n' and vice-versa. Life saver for cross-platform developers.

indent: If you use vim for coding and do not want to indent some code file by hand. This is really good.

Doxygen: For generating documentation if written in javadoc files for source file in any language.

gftp: This is graphical client for ftp, ssh, http file transfers. It allows resume and asks for conflicting files whether they should be overwritten, resumes, skipped etc.

FileZilla: Similar to gftp above. But it also allows parallel connections to various sites.

Wireshark: I cant say that it is not famous. But it is extremely useful tool that I have used many many times to debug network problems. It is a must for every network administrator.

phpMyAdmin: It can be used to manage MySQL database using web browser from any where very easily. Best part is export options to various formats and easy backup and restore options.

phpPgAdmin: Similar to phpMyAdmin, although not as powerful as phpMyAdmin but it does make life easier.

p7zip: Really nice compression and very helpful in case formats zip / rar are blocked for some reason.

k3b: Really good at burning CD/DVDs. We can burn ISO images or create multi-session data DVDs. We can control what OS support is necessary and whether to use extensions like joilet, rocket ridge etc.

kile: Really nice editor for LaTeX documents. It supports good shortcuts for making dvi, ps, pdf etc and compiling and previewing only selected portion of text


Crimson Editor is a great source code editor for Windows. It is simple to use, and has syntax highlighting.


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


At home, everything is open source, but at work (a Microsoft shop) these are the tools I use on a regular basis...

Performance Analysis of Logs (PAL) Tool - powerful tool that reads in a performance monitor counter log (any known format) and analyzes it using complex, but known thresholds (provided).

PolyMon - monitoring solution that can be used to generate email alerts and analyze historical trends of monitor counters and monitor statuses. It is based on the .NET 2.0 framework and SQL Server 2005.(I like the Powershell support.)

WinSCP - SFTP client and FTP client for Windows.

TortoiseSVN - easy to use Revision control / version control / source control software for Windows. It is based on Subversion. TortoiseSVN provides a nice and easy user interface for Subversion.

WinMerge - differencing and merging tool for Windows. WinMerge can compare both folders and files, presenting differences in a visual text format that is easy to understand and handle.

AxCrypt - file encryption software that integrates seamlessly with Windows to compress, encrypt, decrypt, store, send and work with individual files.

Other favorites already mentioned; Notepad++, PuTTY, TrueCrypt, gVim, Wget, Blat, PDFCreator, Wireshark, Subversion.


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.

you should edit this and add some more linebreaks :) – Blorgbeard Jul 4 '09 at 9:26

Leafpad. It's seriously just Notepad for Linux :D


I can't see anyone mentioned bc and gnuplot - the poor man's Excel :) I dare to claim these two are one of the best friends of any student in engineering.


I think Send HTTP tool can be in the list. It is useful to send HTTP request to your URL


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

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


For a complete and useful browser, I use Opera.

It's not open source and only arguably a tool. – Telemachus Jul 4 '09 at 14:56

Bash - I use it every day. Not just for simple stuff, but being able to chain commands together and script the computer gives me so much power.


My favorite tools on a Linux system are telnet and ping. I am not certain if they are OS or not, but still really useful, also netcat in a similar fashion for net system checking/trouble shooting.


I use Cobbler and Koan a lot. It makes remote installations so much easier.


A nifty little tool that never got any attention but was extremely helpful was retty.

If anybody reading this knows assembly and care to do something for this world pleaaaase make retty work with newer systems (It only works on older 32bit systems. And not always...)


Does windirstat qualify?


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