screen: a console-base window manager on steroids

February 14th, 2007 edited by lucas

Entry submitted by Ico Doornekamp. DPOTD needs your help, please contribute !

GNU Screen is one of my all-time favorite Unix tools. According to the official documentation, Screen is a full-screen window manager that multiplexes a physical terminal between several processes.

So, what does that mean ? GNU Screen allows you to run multiple console based applications like editors, shells, IRC clients, newsreaders, etc, all through a single terminal. Screen allows you to switch between applications or layout multiple windows in a single terminal. One of the most nifty features is that the programs running under Screen’s control can be detached - this means they are still running, even though the actual terminal is closed. Later a new terminal can be reattached to a running screen session, even from another host!

Here’s a small demo of a typical Screen session, the true story of Bob the system administrator:

Bob connects to the server and starts a new screen session.

bob@desktop$ ssh bob@server
bob@server$ screen 

Screen displays its welcome message, and after hitting the Return key, a new shell is started.

Screen version 4.00.03 (FAU) 23-Oct-06

Copyright (c) 1993-2002 Juergen Weigert, Michael
Copyright (c) 1987 Oliver Laumann

This program is free software; you can redistribute
it and/or modify it under the terms of the GNU
General Public License as published by the Free
Software Foundation; either version 2, or
(at your option) any later version.

[Press Space for next page; Return to end.]

This shell is now running inside the Screen session. Bob starts his favorite editor…

bob@server:~$ su -
server:~# vi /etc/apache/httpd.conf 

… and does some heavy editing.

ProxyRequests On

Order deny,allow
Deny from all
Allow from 10.0.0. 

/etc/apache/httpd.conf 993,25 94%

But then disaster strikes: The CEO comes in and trips over the uplink network cable, breaking the SSH session!

connection lost. (Connection closed)


Screen to the rescue! Bob starts a new SSH session to the server, and now runs Screen with the -x parameter.

bob@desktop$ ssh bob@server
bob@server$ screen -x 

Instead of starting a new session, screen now reattaches to the running screen session, and Bob finds his editor just the way he left it!

ProxyRequests On

Order deny,allow
Deny from all
Allow from 10.0.0. 

/etc/apache/httpd.conf 993,25 94%

While editing, Bob decides he needs to check his mail. Instead of opening another SSH session to the server, he hits C-a C - that is, he types Ctrl-a and then ‘c’.

Screen now creates a new window, opening a new shell…

bob@server$ mutt  

…and Bob starts ‘mutt’, his mail user agent.

q:Quit d:Del u:Undel s:Save m:Mail r:Reply g:Gro
2 + Dec 22 Daniel Hirschi (0.6K) Implementing s
3 + Jan 06 Ricki Silversto (3.0K) Paycheck
4 + Jan 26 Roberto (1.0K) Read this!
5 C Jan 26 Michel Wraith (9.0K) RE: finished

—Mutt: ~/Maildir [Msgs:5 19K]—(threads/date)—(a)

With the keystrokes C-a 1 and C-a 2, Bob is now able to switch between vi and mutt, from the same console.

Time to go home. Bob hits C-a D, which will detach the current screen session from his terminal, and takes the bus home.

bob@server$ screen -x
bob@desktop:$ logout 

After dinner, Bob decides to finish the job. From his home computer, he opens a new SSH session to the server, and reattaches to the running screen session:

bob@home$ ssh
bob@sever$ screen -x

The editor and mutt are still running, and Bob can now continue his work from home from the point he left.

ProxyRequests On

Order deny,allow
Deny from all
Allow from 10.0.0. 

/etc/apache/httpd.conf 993,25 94%

Screen has been available for ages in both Debian and Ubuntu.

Posted in Debian, Ubuntu | 16 Comments »

zim: a desktop wiki

February 11th, 2007 edited by ana

Entry submitted by Julien Danjou. DPOTD needs your help, please contribute !

Zim is a desktop wiki. It’s a WYSIWYG (What You See Is What You Get) text editor and works like a wiki, so you can have links between your pages, and pages are stored in a hierarchical structure, which makes them easy and to browse. Zim is the perfect application to take notes and keep TODO lists somewhere in an organized fashion. It is very easy to use and you can hide it in the traycon to keep it handy.

It’s written in GTK2-Perl, it’s very small and fast. You don’t need to run a Web server, as required for a standard Wiki like Mediawiki, or to run mono like Tomboy. If you run KDE, a similar program is BasKet, but BasKet is more oriented to note-taking and it it is not supposed to be a desktop wiki.

Files are stored as plain text files and organized in directories, so you can even manage them with VCS like Subversion.

Also, it allows you have multiple repositories independent of each other.

Zim is available in Debian etch and sid (but not in sarge). It’s also available in Ubuntu since Dapper. The only known bug that looks annoying is that it’s currently not possible to print notes from zim (one can still print the text files instead).


Here you have some screenshots taken from zim’s webpage:

The editor window with all widgets visible.

Minimalistic editor window with some links.

Showing the calendar and spell checking in action.

Posted in Debian, Ubuntu | 7 Comments »

krusader: twin-panel (commander-style) file manager

February 7th, 2007 edited by ana

Entry submitted by Matej Urbančič. DPOTD needs your help, please contribute !

Quick overview

Krusader is the most advanced twin panel file manager for Linux with a bundle of features, that can not be all included in this simple package presentation.

Program description

Krusader as an advanced twin-panel (commander-style) file-manager provides all the file-management features you could possibly want. Its simple and straight forward interface provides great working environment for newbies as well as more expert users. While its features are usually described through extended and advanced functionality, it is basically still a file manager for everyone with simple ways for copying, moving, deleting, packing, editing and viewing files. on more advanced levels it features extensive archive handling, mounted file system support, FTP, an advanced search module, a text viewer/editor, directory synchronization, support for file content comparisons, powerful batch renaming, and a lot of other things only real expert users use.

Krusader follows the same paradigm as legendary console based Midnight Commander and windows rival Total Commander. Among Linux alternatives for graphical interface the closest is GNOME commander.

To be just a bit more verbose, Krusader uses two powerful panels, command line and optional terminal emulator, strong keyboard orientation and with it the ability to perform all functions without the mouse. Or with it, if you prefer it that way. It has context-dependent invocation of scripts and programs, history of almost everything, virtual file systems for remote connections, support for many archives, search results and synchronizer, a really powerful internal viewer and editor, advanced searching capabilities on the file system, but also inside archives and search content on remote file systems.
It has several panel view modes via the PopUp panel, locate GUI frontend and separate synchronize directories, mount-manager and disk usage module. It’s archive handling capabilities are wide in features and supported archives types. It utilizes many checksum creation-verification mechanisms, calculates occupied space of files and folders, archives and remote file systems, file splitter and synchronized browsing, it provides directory comparison and filtering and also file compare by content via external diff programs. It integrates powerful renaming via Krename. It simplifies overview and changing of file permissions and ownership with support for numeric permissions, selection filters in synchronizer and searcher. It is fully mimetype-aware, uses tabbed panels and integrates editor/viewer.


Screenshots from Krusader homepage.
Click on picture to see large version.

Additional Information

  • Homepage:
  • Forum: krusader phpBB
  • Programming language: C++ on Qt/KDE framework.
  • Archive support: ace, arj, bzip2, deb, gzip, iso, lha, rar, rpm, tar, zip and 7-zip.
  • Connections: ftp, sftp, lan, samba, NFS, fish.
  • Checksum: md5, sha1, sha256, sha224, sha256, sha384, sha512, tiger, whirlpool, cfv and crc.
  • External diff support: Kompare, Kdiff3 or xxdiff.
  • Recommended packages: krename, kompare, kmail.
  • Availability: Latest version are available both in Debian and Ubuntu. You also have an updated distro list at Distrowatch.

Last words

Krusader project gets a lot of appraisal in reviews. Still, it’s twin panel paradigm somehow, makes users distant. From early beginnings of thin panel file managers, the idea of constantly connected source and destination panels gives an impression of geeky interface and usage. It gets down to simple solution. Use it once and you will never look back.

Posted in Debian, Ubuntu | 1 Comment »

einstein: Puzzle game inspired on Einstein’s puzzle

February 4th, 2007 edited by ana

Entry submitted by Kari Pahula. DPOTD needs your help, please contribute !

Einstein is a game for playing a type of puzzle, attributed to Albert Einstein (hence the name). In its original form, the riddle asks the question “Who owns the fish?” and the player is given hints like “The Englishman lives in the red house” and “The owner of the green house drinks coffee”. The riddle can be solved by placing the five neighbours to the correct order and deducing the nationalities, house colors, favorite drinks, pets and the type of cigarettes they smoke.

In Einstein, the player is given 6 groups of different types of tiles, with 6 tiles in each and a number of hints. Only one type of tiles can be found in a row. There are four different types of hints.

  • X is in between Y and Z hints tell that the three tiles in question are in successive columns, but the order of Y and Z is not fixed.
  • X is on the right side of Y hints tell how the two tiles are situated relative to each other, but they may have one or more columns in between of them.
  • X is next to Y hints tell that the two tiles are in neighbouring columns.
  • Finally, the X is in the same column as Y hints tell that the two tiles are, well, in the same column.

The gameplay consists of elimination and deduction according to the hints. For example, the “x … I” rule above reveals that “x” can’t be in the rightmost column since that would leave no room for having “I” anywhere. A click of the right mouse button removes that tile from consideration. Left clicks are conversely used to mark that the tile in question is in the claimed position. Unneeded hints can be removed from view by right clicks too.

Random clicking or guessing rarely lead anywhere, since the game mercilessly declares the game over from one wrong guess.

Einstein’s homepage is at
It is available in Debian unstable and Etch. And in Ubuntu since Feisty.

Posted in Debian, Ubuntu | 4 Comments »

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