no md5sums and Checksum mismatch on 8.4.2.llts

The MD5 sum is mainly used for checking ISO file and large downloads. If a file fails MD5 check then the file has been garbaged in transit from hosting server to your system.

If you are using Ubuntu you should not be using su as this involves enabling the root account which is disabled for security reasons. It also makes your terminal use the root profile as you have su'd to root. You should use

sudo -i

to get an interactive sudo which will promote your privileges as well as use your profile for programs and files.

You cannot "Change the MD5sum of a file" without modifying the data which in this case will involve redownloading the file.

If I have not answered your query, can you please clarify your question as the way you have worded your question is confusing to me.

Thanks

ok,soory about the confusion.
the ones that have no md5sums can i fix them.to md5sums?
i have a book but it makes a new directory,i dont think thats right.
next i have several checksum mismatches,
i found them to be sha1sums
can these be changed without affecting later updates?
how would i go about it,if i can?
thank you

ok,soory about the confusion.
the ones that have no md5sums can i fix them.to md5sums?
i have a book but it makes a new directory,i dont think thats right.
next i have several checksum mismatches,
i found them to be sha1sums
can these be changed without affecting later updates?
how would i go about it,if i can?
thank you

You can generate MD5 sums for the files. I am unsure if they are convertable but you can check the SHA1SUM of a file with

sha1sum <file> and compare. I got this from http://linux.about.com/library/cmd/blcmdl1_sha1sum.htm

I am unclear of your book making a new directory due to lack of information. Where is the folder? Why is a folder needed? etc....

Thank you for your paitience.
the book i am referring to is unbutntu toolbox by chris negus.
any ways,i tried the approach you suggested,for sha1sums,i found the checksum mismatches i have to be all sha1sum files so that is all good.
then i used sudo -i
debsums_gen `at` (for that one only),made a md5sum.
then did a debsums -l....it listed at,then said cant open ,etc..i knew that would happen.you have to be root or something to open it.that i think i understand.
Question?
if I continue to make the md5sums will that interfere with any new downloads or affect anything?
i will not ask you anymore questions about this and i thank you for your help.
what i am trying to do is understand the system and how to fix things.
should i go ahead and make the mdsums or leave alone
the ones i am referring to do not come with md5sums
thanks again

thanks for the help
peace