Help with understanding the ubuntu customization process

[JeyPeyy]

I'm doing this project at school where I should do my own custom Linux-distro. I chose to customize Ubuntu to do this. Here's the website: http://winuxos.tk/ (lol @ dot.tk, I know, but I haven't had the time setting up a server yet ). I've mostly worked with this.

So now I have to write what I have learnt, but I don't understand everything. Especially not the "Putting the CD together"-part. So, here's some questions:

• Is filesystem.manifest really needed? Won't the installer copy everything from filesystem.squashfs?
• What is that 'sed' thingy? I can't find anything about '-i' in the man page
• How do md5sum work?

[Sorivenul]

• Is filesystem.manifest really needed? Won't the installer copy everything from filesystem.squashfs?
• What is that 'sed' thingy? I can't find anything about '-i' in the man page
• How do md5sum work?

filesystem.manifest, to my knowledge, contains the files installed within the squashfs, and the filesystem.manifest-desktop contains packages that will be installed during installation.

sed is a "stream editor". It is popularly used to do search-and-replace for specific text in a file. "-i" means "in-place", and edits the specified file in place, making a backup as necessary. The syntax would be like:

sed -i[SUFFIX] filename

[SUFFIX] would be what would be appended to a backup copy of the file, AFAIK.

md5sums are, in reality, a pretty advanced topic dealing with algorithms. We make light use of them for checking file integrity. Basically, the md5sum command hashes the information passed to it (in the case of a LiveCD, it is an ISO image), and returns a corresponding checksum. On the user end, they can likewise perform an md5sum, to compare to the original, to make sure the file hasn't been tampered with or corrupted.