They make portable software for Windows, we all know that. I keep a USB drive with all the stuff I need or might need if I'm away from home. I also keep a lot of diagnostic and repair apps on it (Revo uninstaller, Ccleaner, Defraggler, Hijackthis, etc). I was wondering if there is portable software for linux and if so what are the best ones to carry with me. I'm only talking about repair and cleanup applications right now.

Since the software comprising a Linux-based system is Free and Open Source, there is nothing prohibiting the bundling of the operating system with the tools typically needed for rescuing a system. Hence it is more common -- rather than having a disk or pendrive containing programs which can rescue a system (which begs the question: how can such programs run on a system in need of "rescue"?) -- to have a complete, bootable rescue system containing an operating system plus all of the needed tools.

Therefore, "linux" offers options such as SystemRescueCd and Gparted Live, in addition to many of the traditional GNU/Linux distro CDs being able to function as a rescue CD to a usable system (for example, I often use a Slackware installation CD to rescue Windows systems).

I'll look into SystemRescueCd and Gparted Live, that's what I was wondering. I've never had to fix a Linux system, and I don't know enough at the moment to do it but I will eventually I'm sure. People i associate with know I've been advocating it and some will try it and need help.
Thanks.

I recommend GParted Live too. It's quite cool toolset with hard disk problems.

But nearly any Live distribution is good in tight situation. My friend had problems with MS Windows when I was visiting. He had urgent need to send e-mail, but Windows refused to work. I had some Linux magazine with me. It had DVD with several Linux distributions, so I booted his PC with PCLinuxOS, one Linux distribution which I had not used at all before. In ten minutes he could use his PC and Internet connection. He had web-based e-mail so he could send his e-mail... We also checked his Windows partition and rescued some information. Later he told he had re-installed MS Windows, so he had everything working, but he had also bought some magazine with Ubuntu Live DVD just for future emergencies...

You can download systemrescue here.
On their site they have instructions how to put it on USB stick.
http://www.sysresccd.org/Download
Gerard.

Upon Tux's recommendation I've already downloaded and burned a copy of SystemRescueCD and Gparted Live. I haven't ran into a situation where I was asked to fix a linux system yet but when it happens I plan to be educated enough and prepared enough to handle it. This is a good start. thanks again.