Logitech has a great selection of USB mice for all operating systems and they often work without installing any software. Sometimes to get the most out of it however, you can configure your xorg.conf file on Ubuntu 12.04 and some previous Ubuntus. After plugging in the Logitech M510 USB wireless laser mouse, make sure the batteries are in and it is turned on. Then put this code into your /etc/X11/xorg.conf file:


Section "InputDevice"
Identifier "Logitech Mouse"
Driver "evdev"
Option "Protocol" "evdev"
Option "Name" "Logitech USB Optical Mouse"
Option "Phys" "usb-*/input0"
Option "Device" "/dev/input/by-id/usb-Logitech_USB_Receiver-mouse"
Option "Buttons" "8"
Option "ZAxisMapping" "4 5"
Option "Resolution" "1200"
Option "CorePointer"
EndSection


Note: If your xorg.conf file already has a section labeled “InputDevice”, replace it with this one.

It is recommended that you copy your current xorg.conf file to another one using the “cp” command before using this code. After it is done, restart your computer (logout/login might also work).

No additional software required. First, create a directory in which to mount the ISO.

mkdir -p ~/media/iso

Then, to mount it:

sudo mount -o loop /home/path/to/my_fun_dvd.iso ~/media/iso
nautilus ~/media/iso

The last line is to open the mounted directory in a visual file browser called Nautilus.

If you end up doing this often, you can create a bash function. Put this at the end of your ~/.bashrc file:

function mountcd {
sudo mount -o loop $1 ~/media/iso
}

Save the file, reload it in bash using this command

. ~/.bashrc

That’s (period)(space)~/.bashrc — the period is a command in bash that reloads the script file without having to launch the terminal again.

Now you can do this in the terminal:

mountcd ~/Downloads/my_cool_dvd.iso

And your DVD ISO will be ready for viewing in the ~/media/iso directory (the tilde character means your home directory, /home/john). In Ubuntu 12, by opening the folder containing the DVD files, it will prompt you to open with VLC media player:

I recently wanted to make a change — actually a string replacement — in every file in the current directory and all directories beneath it, perhaps filtering by file extension. In this case, I wanted to change four spaces to a tab character in every .php source file. I created a small BASH shell script file to do this, though you could also just run the command directly at the command line:

find . -type f -name '*.php' -exec sed -i 's/    /\t/g' {} \;

Explanation:

• find lists all files, one per line, in the current directory and all subdirectories recursively
• . (period) means current directory
• -type f only list files, not directories.
• -name ‘*.php’ only if the name matches * (wildcard) with “.php” at the end
• -exec execute the following command for each result that matched
• sed -i ‘s/    /\t/g’ replace, or substitute, one string for another. I’m searching for four consecutive spaces and replacing with t, meaning tab character. the /g at the end means global, replace each instance wherever it may appear in the file on each line. -i means “edit file in place” so the modified file is saved back to itself.
• {} this inputs the file for the sed command
• \; I think this finishes the -exec parameter for find. Don’t forget the backslash

To change spaces to tabs or tabs to spaces, you can also look into the expand and unexpand commands.

Overall I highly recommend learning the sed command for quick and easy find & replace operations in text files.

More examples of the find command with -exec:

Delete all directories matching a name, such as CVS, under the current directory:

cd /path/to/myproject/directory/src
find . -type d -name 'CVS' -exec rm -rf {} \;

Here’s a simple way to find how much disk space is taken up by each folder in a directory, and sort it by size. This works in pretty much any Linux distribution (Ubuntu, Fedora, CentOS, and more).

du --block-size=MiB --max-depth=1 | sort -n

• du is the disk usage and will, by default, recursively traverse every directory of the current one, listing the size of the directory by bytes. Without options, it isn’t very helpful (press Ctrl C to stop the process safely)
• –block-size=MiB will convert the bytes amount to megabytes (or Mebibytes), so instead of showing 9437184 (bytes) it will show 9 MiB
• –max-depth=1 will only list size of directories in the current directory. 2 will traverse an additional level down, and so on.
• | sort -n will transfer, or “pipe”,  the output of the du program to the sort utility which simple sorts lines sent to it. -n tells it to sort numerically.
• If you want to sort in reverse order, simply change n to rn

statik@Phenom:~/Pictures$ du --block-size=MiB --max-depth=1 | sort -n
1MiB ./icons
1MiB ./USTM
1MiB ./vector
1MiB ./Webcam
3MiB ./animated
3MiB ./wallpaper
8MiB ./UltraMiami
688MiB ./2010
1600MiB ./2011
2306MiB .

alias duinfo='du --block-size=MiB --max-depth=1 | sort -n'