It is used to terminate the active process.

kill <process_number (Num.PID)>

If the process is not generated by you, for kill it use the command: sudo kill Num.PID
If the process is hard to terminate, use the command: sudo kill -9 Num.PID

UP

pstree

It show the tree process.

UP

cat /proc/cpuinfo

It show the HW version

lsusb

It show the USB device connected to your PC

UP

ls -l

It show the contents of the directory where you are.

ls -alp

It similar to ls -l but plus it show the iden files.

Examples of ls -l

0123456789 A B       C      D     E           F

drwxrwxr-x 2 enrico enrico 4096   gen 6 2013 CNC

-rw-rw-r-- 1 enrico enrico 307018 set 22 00:07 C:\nppdf32Log\debuglog.txt

From left to right, below, the explanation of the result.

0) it tell us if is a file or a directory (d)

1...9) it tell us the permission and means:
r reading
w writing
x execution
- not assigned

The permission are groupped for:
1,2,3) permissions assigned to the owner
4,5,6) permissions assigned to the group
7,8,9) permissions assigned to all the users

A) indicates the number of connections to the component while for folders indicates the number of extra blocks.
B) it is the name of the owner of the file or the directory.
C) is the group membership
D) dimensions
E) date and time of creation or last modification

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chmod

It is used to change the permission on files.
In the example below we gave all, all permissions.
chmod a=rwx <nome_file>

chmod -R <permission> <directory>

It is used to change the directory permission and also the permission on all the files that are in the directory.
The example below gives to all, all permissions:
chmod -R 777 <directory>

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chown <owner or group> <file_name>

It is used to change the proprietary of the files

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cp <source_file> <destination_file>

It is used to copy file

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rm <file_name>

It is use to delete the file

mv <name1> <name2>

<name1> <name2> is file or directory, it is possible that before use this command is necessary login as super user sudo mv <name1> <name2>

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cron

This is a scheduler that allows you to run commands at scheduled times or to repeat it with fixed intervals.
See here:
http://en.wikipedia.org/wiki/Cron
and here.
To see my example look here.

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nano <file_name>

It allows us to modify the specified file using the nano editor.

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sudo apt-get install <package>

It is used to install the packages.
EXAMPLE:
sudo apt-get install gedit
Install gedit

sudo apt-get remove <package>

       Remove the package and all dependencies not used from other packages.

sudo apt-get remove <package>

       Remove all dependencies not more used from the package.

sudo apt-get purge <package>

        Similar to apt-get  remove, but also remove the configuration files related to the package.

sudo apt-get update

It allows us to update the packages in our system.
If a package requires the installation or removal of new dependencies the package will not be updated by the update command.
To effect these changes will also have to use upgrade command (see below).

sudo apt-get clean

        Removes the files are no longer used in our system.

sudo apt-get autoremove

        Removes files marked as no longer used

sudo apt-cache search <word>

        It is use for find a packages that contain the specified word

sudo apt-cache show <package>

       This command show the information regarding the package

sudo apt-cache depends <package>

        This command show the packages that are necessary for a package.
       

sudo apt-cache showpkg <package>

        This command show the version, the reverse depens and the dependecies of a package
        Example:

Manage your WiFi / Network

ifconfig

iwconfig

cat /proc/net/wireless
watch -n 1 cat /proc/net/wireless

Wavemon WiFi monitor