Online Button / Badge Maker - Free

Know those small buttons or badges that you see around? Well know there’s a website that allows you to make your very own customised badge! You can put any text that you want on it, and have any combination of colours. Pretty nifty!

I made a button badge for myself, and here’s how it looks like:

Interested? Check out the site here: http://kalsey.com/tools/buttonmaker/

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Free Online Tool - Convert Movie Files (Avi, RM, MOV, etc)

This is unbelievable. I had a movie clip in .mov (Apple’s Quicktime format) and I needed to convert it into .avi so that I could insert it into a Windows Powerpoint. Apparently if I had a Macintosh, the Macintosh version of Powerpoint could play .mov natively. But oh well, shrugs.

So I looked online for solutions, because I really didn’t want to spend any money to buy a conversion software. Guess what? I found my answer - free online conversion tools!

These websites are absolutely fantastic! They’re fast, easy to use, and convert A LOT of formats. I found two - and I used the first one, which was Zamzar. Check them out:

http://www.zamzar.com
http://media-convert.com/

Zamzar was absolutely idiot-proof. I simply chose the file that I wanted to convert on my computer, and then it uploaded the file. It was only 2mb, so I didn’t have to wait very long. After which, I received an email telling me that my file was converted. There was a link in that email which brought me to the download page where I could download my movie in .avi format - amazing!

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What is a proper backup?

Simply storing duplicate copies of your critical data on the same device is not a proper backup. The true definition of “BACK UP” is storing TWO or more copies of critical data on TWO separate storage devices!

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Example FTP Session in UNIX

UNIX has a very powerful command line interface, and one of the things that you can do is remotely access a UNIX server. FTP is one such remote protocol that allows for the transfer of files easily. This FTP example shows how to copy, rename, and delete files.

ftp alvinpoh.com

This just means you want to open a FTP connection to the ftp server at “alvinpoh.com”. Once connected, you’ll be prompted to log in using a username and password. There are public ftp servers which provide anonymous access. This just means that you can log in using the username “anonymous” and your email address as password.

So what do you do once you’re connected?

ftp> ls

This command prints the names of the files and subdirectories in the current directory on the remote computer. So let’s say you see that there’s a folder named “public_html” inside.

ftp> cd public_html

Running this command changes the current directory to the subdirectory of “public_html” (this subdirectory must exist, if not, an error would be shown). Now that you’re in “public_html”, let’s go back up again.

ftp> cd ..

So this changes the current directory to the parent directory (where you were at). Now let’s assume we want to transfer a photograph to our remote server. So, first of all, we need to determine where our photos are stored in our local computer (the local computer’s the computer that you’re physically at).

ftp> lcd my_photos

Changes the current directory [em]on your local computer[/em] to “my_photos”.

ftp> !ls

A ‘!’ in front of the command will execute the specified command on the local computer. So ‘!ls’ lists the file names and directory names of the current directory on your local computer. Let’s imagine that after you run !ls, you find that there’s a file named “photo.jpg” that you want to transfer to the remote computer.

ftp> ascii

This changes to “ascii” mode for transferring text files. But we’re not transferring text files, so…

ftp> binary

So this changes to “binary” mode for transferring all files that are not text files.

ftp> put photo.jpg

Uploads a copy of the file photo.jpg from your local computer (remember, we’re at the “my_photos” directory) to the remote computer. Warning: If a file exists with the same name, it will be overwritten. Say you find a photo on the remote computer that you’d like to download to your local computer - no problems!

ftp> get interesting_photo.jpg

This will download the file interesting_photo.jpg from the remote computer to your local computer (remember, we’re still at the “my_photos” directory). Warning: If a file exists with the same name, it will be overwritten. But what if there’s a lot of files that you want to download? Well, there’s a useful twist on the get command for that!

ftp> mget *.jpg

With the mget command, you can now download multiple files. I suppose the “m” stands for “multiple” or “mass”. In this case, our command downloads all files that end with “.jpg” to our local computer.

ftp> mput *.jpg

Similarly, this command uploads all files in your current local directory that end with “.jpg”.

ftp> mdelete *.jpg

That’s not all - there’s a mdelete command that deletes all files that end with “.jpg”. Neat? But if you tried these commands, you’ll find that if there were 1000 files, you’d had to confirm the action for each of those 1000 files. Here’s a workaround for that.

ftp> prompt

This toggles interactive mode on or off so that commands on multiple files are executed without user confirmation. You’ll see a message telling you “Interactive mode off” or “Interactive mode on” after running this command.

ftp> quit

We’re done, so type that command to exit the ftp program. Or alternatively, try typing “bye” for a friendly version of that command! And if you’re stuck at any point of time, you can always get more help.

ftp> help

This is the help function which lists the commands that you can use to show the directory contents, transfer files, and delete files.

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Common Useful UNIX Commands

If you’re new to UNIX-based systems (e.g. Linux), the interface can be daunting, especially since there’s no GUI, and you might need to use the shell command line interface to remotely access a computer.

There are a few basic UNIX commands for performing common tasks that you should know of, which allows you to navigate and interact with the system.

MOVING & CHANGING DIRECTORIES

cd dirname

This command allows you to specify the directory name that you want to move to.

Examples:
cd public_html
cd home/alvin

cd ..

Moves one level up from the current directory. Take note of the space between “cd” and the two periods. This is different from Windows, where “cd..” (without the space) would work too. For example, if you are in /home/alvin, use this command to change your folder to /home.

If you want to move up 2 levels, then use “cd ../..”

cd

Changes directories to your default login directory. In UNIX systems, you are automatically placed in your login directory, or home directory when you log on. Performing this command brings you back to that login directory.

IDENTIFYING THE CURRENT DIRECTORY

pwd

Sometimes you need to know what directory you are in. This command in UNIX shows you what directory you are in currently.

LISTING THE CONTENTS OF THE CURRENT DIRECTORY

ls

Lists all files and subdirectories, except for those that begin with a period, such as .links files.

ls -al

Lists all files and subdirectories (including those that begin with a period), with owners and sizes.

CREATING, REMOVING, AND MOVING DIRECTORIES

mkdir dirname

Creates a subdirectory named dirname in the current directory.

rmdir dirname
Removes the subdirectory named dirname from the current directory.

mv dir1 dir2

Moves (or when you look at it from a different angle, renames) the subdirectory (and its contents) from dir1 to dir2. E.g. “mv notes ../notes” will move the notes folder up one level.

FILE MANIPULATION

wc filename

Line, word, & char count of filename.

cat filename

List contents of filename.

more filename

List filename contents by screen.

cat file1 file2 >file3

Concatenates files file1 & file2 into file3.

cmp file1 file2

Compares files file1 and file2.

cp file1 file2

Copy file file1 into file2.

split [-n] filename

Split filename into n-line pieces

mv file1 file2

Rename file file1 as file2.

rm filename

Delete (remove) filename

grep ‘asdf’ filename

Outputs lines in filename that match asdf

diff file1 file2

Lists file differences between file1 and file2.

head filename

Output beginning of filename.

tail filename

Output end of filename.

USER MANAGEMENT & INFORMATION

quota

Displays disk quota.

date

Prints date & time

who

List logged in users with some information such as their IP and time logged in.

whoami

Displays the username of the current user (ie YOU).

finger username

Output user information of username.

history

Display recent commands performed by you.

!n

Submit recent command number n, e.g. !18 repeats the command number 18 in your history list of commands.

passwd

Changes your password.

CHANGE GROUP AFFILIATION OF DIRECTORIES OR FILES

Note: You must own the file or directory you want to change and you must belong to group you are changing it to.

chgrp groupname filename

Changes group affiliation of filename to groupname.

chgrp -R groupname dirname

Changes group affiliation of dirname and all files within dirname to groupname.

GIVE GROUP MEMBERS WRITE PRIVILEGES

Note: You must own the file or directory you want to change.

chmod g+w filename

Gives the group write privileges to filename. Any member of the group affiliated with filename can then change or delete the file. Or, use g-w to remove group write privileges.

chmod -R g+w dirname

Gives the group write privileges to all files within dirname. Any member of the group affiliated with dirname can then change or delete any file within dirname. Or, use g-w to remove group write privileges.

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