by default, firefox buttons and input fields are ugly Windows-95-style - this does not look good at all in a modern GNU/Linux environment IMHO; so I did a wee bit about it; the google.com index page looks like this for me now:

To type a lot of one character (or a backspace) when using Bourne Shell or Bash, hit Alt, enter the number of times to repeat, then hit the character to be repeated.

Hit Ctrl+l (lowercase L, not uppercase i) to clear a console without typing out "clear".

You can use Qemu to boot a CD ISO image you downloaded before you even burn it. This could be useful for just checking it out before you decide to spend a CD for burning it or to take screenshots you otherwise wouldn't be able to from the real bootup.

Here's a simple command to do it:

qemu -cdrom cdimage.iso

You can even install a CD image on a special virtual disk you can create on qemu. This disk is actually not a disk, of course, but a disk image which contains free space that can be used within qemu emulation.

Copy a file to host:
cat FILE|ssh HOST "cat ->FILE'S-LOCATION-ON-HOST"

Copy a file from a host to current host:
ssh HOST "cat FILE"|cat ->FILE'S-LOCATION-ON-CURRENT-HOST