Without passing any options, wc returns line, word and byte counts for its input.  Say we have a file called foo.txt with the following contents:

foo
foo

If we run wc against this file we will get:

$ wc foo.txt
2 2 8 foo.txt

Notice, however that the byte count is two bytes too many for what you’d expect. A quick glance at the content of the file tells us that there are only 6 characters, and therefore only 6 bytes in the file. Even if we try to run wc with the character specific option “-m”, we get the same:

$ wc -m foo.txt
8 foo.txt

The same thing happens whether we use the “-c” option for bytes or the “-m” option for characters. This is because of the unseen newline character at the end of each line. Even if we echo a line of text to wc, we get the same effect.

$ echo foobar | wc -m
7

If you want a true count of the characters, you have to take the newlines into account. We can remove the newlines from echo easily enough with tr:

$ echo foobar | tr -d '\n' | wc -m
6

Actually, we can do it even easier, by using echo‘s “-n” option which removes the newline characters from standard output:

$ echo -n foobar | wc -m
6

But if you want to pass a file to wc and get an output that doesn’t take the newlines into account, you’re probably stuck using tr

$ cat foo.txt | tr -d '\n' | wc -m
6

The major derivatives of Ubuntu are well known, but what about the others? Just because they aren’t as popular doesn’t mean they don’t have something to offer! We introduce five of the least known, yet simply outstanding distributions.

The article gives a nice overview of

• DEFT – the Digital Evidence & Forensic Toolkit: a distro running LXDE and targeting foresnic work with packages like Sleuthkits’s Autopsy, ophcrack and ClamAV
• Element – a home theater PC distro targeted at HDTVs
• Jolicloud – you guessed it: a cloud-based distro for netbook users
• moonOS – an elegantly, artsy distro using the little-known Enlightenment window manager.  it looks to have even more style than Fluxbuntu did back when it was an actively developed distro.
• wattOS – a lightweight, power-efficient distro (think DSL, Puppy and Tiny Core) recommended for recycled PCs

It looks like Ubuntu 9.10 comes with some handy tools for checking the health of your hard drive.

• Palimpsest – GUI tool
• devkit-disks – CLI tool

Check out this blog on linux.com for screenshots of Palimpsest.  Although, beware, launchpad currently shows a bug related to the error that shows up in the screenshots.

If you happen to get what you think is a false positive for SMART value 5 “Reallocated Sector Count”, check it with the command line tool devkit-disks by running:

sudo devkit-disks --show-info /dev/sda

Changing the /dev/sda to match whatever disk you want to check against.  If you’re not sure what /dev device to look at, you can run

sudo fdisk -l

To get information on all the hard drives in your system.

I posted recently in wipe your… about secure document deletion.  Until today, I hadn’t tried any of the methods mentioned in that post for securely deleting individual files.  So, since I needed to securely delete some files, I finally gave it a go.  I used shred to delete some files.

To delete an individual file, try this command:

shred -uzv -n 1 [filename]

The options are as follows:

• -u dictates removal of the file after the command finishes (although, I’m not sure why you wouldn’t want to remove a file after you have shredded it)
• -n followed by a number, dictates the number of passes (without this option, shred defaults to 25 passes)
• -v dictates a verbose output
• -z dictates a final pass (beyond the passes indicated with -n) of all zeros

I use just one pass, but lots of people cling to the belief that magnetic moments can be recovered if not sufficiently overwritten. After reading Overwriting Hard Drive Data: The Great Wiping Controversy, however, I gave up the notion of needing multiple passes. I use the -n 1 option to overwrite the data with a random string and then follow it up with the -z option to essentially cover shred‘s tracks and make the drive space read like it had never been written to.

While the command above worked really well for deleting individual files (or even multiple files within a directory by using the star wild card “*” for the filename) it made for slow work drilling down through a very intricate directory structure to shred all the files in a given directory. Unfortunately (or perhaps fortunately) shred doesn’t have a recursive option.

So I had to get creative. I tried using find and piping the results to xargs shred, but I quickly discovered that xargs doesn’t have a convenient way of dealing with spaces in file names, (and I had lots of those). So I went one step further and used the following command:

find [top-directory] -type f | sed 's/ /\\ /g' | xargs shred -zu -n 1

The find command pipes the stream to sed which replaces all of the spaces with escaped spaces and then pipes that output to xargs shred.  After you have recursively deleted all of the files in your directory using the above command, you can then remove the folders recursively with this command:

rm -rf [top-directory]

The -r option makes rm (short for “remove”) run recursively, and the -f option forces it to delete everything without prompting you.

WARNING: these are very dangerous commands.  Just like I mentioned in wipe your…, use these commands at your own risk.  They result in permanent deletion of the files and directories in question.  Once you have run these commands, there is no going back.

This totally works. However, I found a simpler solution than their method. So far, every Flash video I play ends up in /tmp as an extention-less file that begins with “Flash”. Try running

ls /tmp | grep Flash

If you get just one return, then you can run

find /tmp -name "Flash*" -exec cp '{}' flash.flv ';'

This will find anything in /tmp that starts with “Flash” and copy it to your home folder as “flash.flv”. Of course, you still have to wait until the video finishes buffering before running the find command.

Step 1: Convert the file to MPG

Instead of using transcode to rip apart the input file and then multiplexing the new files back together with mplex, you can use ffmpeg to do the full conversion. It should work for any video file. I have had success using it on AVI, MKV and FLV files, regardless of the codecs inside the wrapper.

For the sake of this tutorial, we will generate an output file with the name “output.mpg” that we will then reference in other commands. Change “input.file” to the name of the file that you want to convert.

ffmpeg -i input.file -target dvd -copyts -aspect 16:9 output.mpg

Note: if your file’s aspect ration is 4:3, use that ratio instead of 16:9. Also, if you need PAL instead of NTSC, change the -target dvd to -target pal-dvd.

Now if you get an error (like many Ubuntu 9.04 users have) indicating “Unknown encoder ‘mpeg2video’”, try this trick that I found at the Paper Inside blog. Basically, it wipes out the ffmpeg that you currently have (with stripped libraries) and reinstalls it with the unstripped libraries. Be sure to capture the full line on the last command, as it goes on for quite a bit.

sudo apt-get purge ffmpeg

sudo apt-get update

sudo apt-get install libavcodec-unstripped-52 libavdevice-unstripped-52 libavformat-unstripped-52 libavutil-unstripped-49 libpostproc-unstripped-51 libswscale-unstripped-0 ffmpeg

Note: Paper Inside’s command installs libavcodec-unstripped-51 and mine installs libavcodec-unstripped-52. I guess the repos must have changed since his post, as I couldn’t find 51. The 52 library worked perfectly for me, though.

Step 2: Make a folder for your your titlesets to go into

The folder needs to be in the same location as your MPG file you just made. For this example, we’ll create a folder called DVD:

mkdir DVD

Step 3: Make an XML file

Again, in the same location as the file and folder you just made, create a text file called dvdauthor.xml:

touch dvdauthor.xml

And then populate that file with the following content, using your favorite text editor:

<dvdauthor dest="DVD">
<vmgm />
<titleset>
<titles>
<pgc>
<vob file="output.mpg" chapters="0,5:00,10:00,15:00,20:00"/>
</pgc>
</titles>
</titleset>
</dvdauthor>


Note the double quotes around the name of your MPG file. You can make the chapters at whatever increments you want by editing the time values. Also, if you want your finished DVD to play more than one video, just add a second pgc section to you dvdauthor.xml file like this:
<dvdauthor dest="DVD">
<vmgm />
<titleset>
<titles>
<pgc>
<vob file="output.mpg" chapters="0,5:00,10:00,15:00,20:00"/>
</pgc>
<pgc>
<vob file="output2.mpg" chapters="0,5:00,10:00,15:00,20:00"/>
</pgc>
</titles>
</titleset>
</dvdauthor>


Step 4: Convert the MPG file to DVD titlesets

This dvdauthor command will populate the DVD folder you made with an AUDIO_TS and VIDEO_TS folder and populate the VIDEO_TS folder with the .vob and other files necessary for DVD playback.

dvdauthor -x dvdauthor.xml


Step 5: Convert the titlesets into an ISO

This mkisofs command will take the DVD titleset folder you just made and copy it over to an ISO file that will be ready to burn to a DVD. The syntax for mkisofs is pretty straightforward, though different from some other input/output tools. In order to generate my .iso files, I use the following options in mkisofs:

• -o to indicate the output file location and name
• -V to set the volume label on the .iso file (which some DVD players and media players will display when they begin playing the DVD or ISO file)
• -dvd-video to generate a DVD-Video compliant UDF file system

In the command below, change the output argument (after the -o) to whatever you want the ISO file to be called and the volume label argument (after the -V) to whatever you want the volume label to read. The final argument is the input, and it references the DVD folder that we made above (the one we populated with our titlesets,) so leave it the same unless you put your titlesets somewhere else.  If so, remember that the input for mkisofs should reference the folder that contains the AUDIO_TS and VIDEO_TS folders.

mkisofs -dvd-video -o mydvd.iso -V MYDVD DVD

Step 6: Burn the ISO file to a disc

Now you have a DVD image ready to be burned to a DVD disc. You can check the image before burning by opening it with VLC. It should play in VLC just like any other video file. And while there are probably command line tools for burning to DVD, I always use Brasero’s “burn image” option. You can burn the ISO to a DVD-RW disc to try it out in your DVD player before committing the image to a DVD-R.

When I started usng Xubuntu last year, I was really impressed with the Thunar file manager’s plug-in for renaming multiple files.  In fact, when I switched over to using Gnome, I made sure to install Thunar to keep that amazing functionality.  I use it all the time for cleaning up directories of media: pictures from digital cameras, music files, videos.  You can use it for folders as well as files.

For Ubuntu-type users (regardless of your distro), assuming you’re not already running an XFCE distro, you can find Thunar in the repositories.  Install it with Synaptic Package Manager or at the command line with

sudo apt-get install thunar

But what if you want to do some bulk renaming from the command line? With an amazing tool like Thunar’s Bulk Rename, you probably wouldn’t have to, but one of the best things about free software is that you can almost always find another way to skin the cat.

I recently ran across the appropriately named rename command.  Check out this tutorial on how to make Perl-based Debian package work for you: How to bulk rename files from the terminal.

And it also looks like KDE has a GUI bulk renamer called Krename.

Try them all and let the rename game begin.

• Changing NT passwords with Linux and CHNTPW
• Change Windows Password from Ubuntu/Ubuntu Live CD

I have used a live-cd that I found here to delete passwords before.  Basically, it boots up a minimal Linux instance and uses the chntpw to delete the passwords.  This tool has the added benefit of automatically finding the location of the SAM file.  The guides above, however, have the benefit of working from any live-cd that has an internet connection (so you can use apt-get to install chntpw).