Insert a disk first.
rawrite image.i a:

You do this for both your boot and root disks.

-rws--x--x   1 root     root       151744 Jun  3 23:40 xterm*

Files can be spotted as suid files by the "s" in the permissions. Xterm will run as root (the owner) giving that process all of the permissions that go along with root access. Suid root files are where many of today's security holes stem from.

To find all of the suid files on your system you can use the following command line:
find / -perm -4000 -print > outputfile

Why are there file permissions?
There are two main reasons for file permissions. Privacy and Security. If you are a user that keeps company information in your account, you don't want a user from a competitor to read those files. As a security issue, the system administrator doesn't like the possibilty of everyone being able to edit important system dependant files.

Let's say you do an ls -lag on a directory and get the following back:

-rwxr-xr-x   1 dopheide users         348 Jun 22 15:04 list.pl*
-rw-r--r--   1 dopheide users        6982 Jul  1 17:54 newsetup.sh
drwxr-xr-x   2 dopheide users        1024 Jul  1 18:18 packages/

The first ten characters are your file permissions. The first character is usually a "-" indicated that this is a regular file. The most notable exceptions are: "d" which stands for "directory" and "l" which stands for "link."

The next nine characters should be divided into 3 sets of 3 characters. The first set detemines the permissions of the owner of the file, in this case dopheide. The "r" stand for "read," the "w" for "write," and the "x" for execute. The second set is the permissions for everyone in the group indicated (users in the cases above). The final set of three determine the permissions for everyone else.

Changing File Permissions
Many times you will need to change the file permissions. Perhaps to give someone else access to execute a file. To do this you need to use the "chmod" command. There are really two ways to chmod a file... one involves letters, +'s, and -'s which I think is way to confusing. The other way, (explained here) uses numbers. We assign each type of permission (r, w, and x) different numeric values.

r = 4
w = 2
x = 1

All we need to do now is some simple math. For each of the three sets (user, group, and other) we just add up the permissions we want to give. For instance, if you want to give read and execute permissions, that would be 4 + 1 = 5. Now you have 3 numbers, separately they indicate the permissions for the owner, group, and everyone else respectively. To change the file permissions you need to sm ash these three numbers together into one three digit number. For example, rwxr-xr-x is the same as 755 (very popular by the way). Now that you have the three digit number all you have to do is: chmod 755 filename

--x =  1 -w- =  2 -wx =  3 r-- =  4 r-x =  5 rw- =  6 rwx =  7

If you are root you can also chown and chgrp, but I'll let you look those up in the man pages. (man chown or man chgrp)

Compiling a Kernel

cd /usr/src/linux make config make dep ; make clean ; make zImage cd /usr/src/linux-2.0.0/arch/i386/boot/ cp zImage / cd / cp zImage vmlinuz cp /usr/src/linux/System.map /boot/System.map lilo
		There are many other ways to make a configuration (such as make menuconfig), but I'm the most familiar with the old text-based method.
		Make a backup of vmlinuz first
		You only need to run lilo if you use lilo.

Trying to save a floppy (for when you get read errors and such)
dd if=/dev/fd0 of=filename
"if" stands for "input file" which, in this case, is the entire floppy. "of" stands for "output file" which will be created. Just use less or more to look through the output file. If you're lucky you might recover some information.