Zeeshan Akhter

Unity is the default windows manager on Ubuntu. It introduced the launcher on the left side of Ubuntu and the Dash to start programs.

Press the “Windows” key to start the dash.

To add new entries to the launcher you can create an “.desktop” file and drag file on the launcher. For example the following creates an entry for Eclipse with different shortcuts for different workspaces.

				
[Desktop Entry]
Icon=application-x-executable
Name=eclipse
Type=Application
Exec=/home/vogella/Eclipse37/eclipse

X-Ayatana-Desktop-Shortcuts=Docu;vogella;business

[Docu Shortcut Group]
Name=Docu
Exec=/home/vogella/Eclipse37/eclipse -data /home/vogella/workspace/docu
TargetEnvironment=Unity

[vogella Shortcut Group]
Name=vogella
Exec=/home/vogella/Eclipse37/eclipse -data /home/vogella/workspace/vogella
TargetEnvironment=Unity

[business Shortcut Group]
Name=business
Exec=/home/vogella/Eclipse37/eclipse -data /home/vogella/workspace/business
TargetEnvironment=Unity

To configure it you can install the compizconfig-settings-manager via apt-get install compizconfig-settings-manager. This configuration manager can be started via the “ccsm” command and allow for example to always show the launcher.

In this tool search for the “Ubuntu Unity Plugin” and then search for “Hide Launcher”. Set it to “Never”.

Ubuntu offers several editors which are installed by default. The most common command line editor is “vim”. Start vim from the command line. vim has two modes, one editing mode and other mode in which you can move within the file. To start editing the file use “i”. Once you want to save press the escape button and write “:wq”. If you want to exit without saving use “:q!”.

A simple editor with a graphical user interface is gedit.

Grep is a command line tool to search for regular expressions. grep will print the matching line to the output and with the –color flag you can highlight the matching strings.

				
echo "hallo hallo" | grep -P --color "h\w"

The following example will search for the number of occurrence of string “abc” in the file “file.txt”.

				
grep -c "abc" file.txt

grep is frequently used together with the find command. For example the following will case-incentive search for the pattern “.*Legacy.*.xml”. through the content of all files and list the files which ends with “.java” and lists these files.

				
find . -name "*.java" -print0 | xargs -0 grep -i ".*Legacy.*xmi"

Use the -r “recursive” option to search a directory and all files included within it.

				
# Search hello in all files and
# subdirectories of the current directory
grep -r "hello" .

The following demonstrates the usage of the find command.

The following calculates the size (disk usage))of a folder “folder1″ in megabyte.

				
du -sh folder1

Use the command “rm pattern”" to delete files. Be careful with the usage of files.

				
# Remove all files which ends with .class in the current directory
rm *.class
# find all files which ends with .class recursive in all directories below the current one and delete them
find . -type f -name "*.class" -exec rm -vf {} \;

To see all running processes on your system use

				
ps -aux

To create a new user via the console use the following commands. This will create the user, set his password and create a home directory for the user and change this ownership of the directory.

				
sudo useradd newuser
sudo passwd newuser
sudo mkdir /home/newuser
sudo chown newuser /home/newuser
sudo chgrp newuser /home/newuser

Careful: This command will allow the user also to execute sudo commands (root).

				
sudo adduser vogella admin

The path environment variable is where the system will look for executable files. To temporay add the directory “/home/vogella/bin” to the path on a shell use the following command.

				
export PATH=$PATH:/home/vogella/bin

If you want to add a directory permanently to the path you can edit / create the file “.profile” and add the following line to the file. Every new directory in the path must be started with “:”.

				
PATH=$PATH:path_to_new_directory

Changes in the “.bash_profile” are only valid after logging out and in again of the system.

The following commands give you an overview of your network connections.

curl is a command line tool to issue and receive http (and other) request. For example if you want to see the HTTP output of a webpage use the following command.

				
curl http://www.vogella.com
// Or
curl -G http://www.vogella.com

If you want to the HTTPrequest header (including the HTTP status codes use the following command. This is for example nice to see if your server deliver a 404 return code for your self-defined error page.

				
curl -I http://www.vogella.com

You can set HTTP header information with the -h flag. For example to request a certain MIME type use the -H’Accept:MIME’ option.

				
curl -I http://www.vogella.com -H'Accept:text/plain'

To use curl behind a proxy.

				
curl -x proxy:8080 -G http://www.vogella.com

For IRC communication you can use the tool xchat. To install it use “sudo apt-get install xchat”.

For Ftp access you can install filezilla via sudo apt-get install filezilla or map the ftp access to a virtual device.

To map the device select your desktop. Select the file menu and the entry “Connect to server”.

The “pdftk” command line tool allows to rework existing pdf files, e.g. extract pages or change the orientation of the pdf file.

You can install it via the following command.

				
sudo apt-get install pdftk

For example to extract pages from an pdf document you can use the “cat” option.

				
# Extract certain pages from a pdf document
# "dont_ask" will override existing files without warning 
pdftk Eclipse4book-20120429.pdf cat 25-27 87-91 95 output Eclipse4-Exercise.pdf dont_ask

If you have LibreOffice installed you can convert .odp files on the command line to pdf files.

				
soffice --nologo --invisible -convert-to pdf -outdir ./pdf *.odp

To connect to your Linux system via telnet or via ssh from windows you can use putty Putty download page

In case your Linux system is runnig under a graphical user interface (KDE, Gnome,…) and you need access to the console, use the Ctrl-Alt-F1 shortcut keys to switch to the first console. To switch back to Desktop mode, use the Ctrl-Alt-F7 shortcut keys.

Ubuntu 11.10 ships with Unity which has a nice quick starter menu. To edit this menu you can install the menu manager via:

				
sudo apt-get install alacarte

To open this type “Menu Manager” in the Dash. Choose “programming” in the left panel. Press “New item” button then. Choose name, command, icon

In the panel click and hold Alt to quick switch/launch apps.

The first thing is to create a shortcut for opening a shell / terminal window. Ubuntu allows to define keyboard shortcuts via the following menu entry.

For example you can assign the hotkey “Ctrl+Alt+X” to “Open a terminal” via the following entry.