.

This is a general purpose document about how to uudecode, download and look at pictures from the Usenet. A lot of what is stated here is valid for other uuencoded binaries as well, but some is not. If you feel that the material here is hard to understand, or need more help, please feel free to contact me at hagie@netcom.com. I want to make these as useful to people as I can, and suggestions are appreciated.

This document is NOT a substitute for the ABP faq, but is directed at newbies who are confused about what uudecoding is, and what to do about it.


What is Uuencoding?

All computer pictures use 256 different numbers per byte to depict the colors of a pixels. Unfortunately, Internet e-mail and the Usenet can only use Ascii, which is about 90 numbers, i.e. A-Z, a-z, and some punctuation. So in order to send these files as ascii, you need to encode them to fit within that small amount of space that it allows. Uuencoding does this, by converting the file into an Ascii-only file.

What is all that gibberish I see when I look at a uuencoded file?

This is an example of a Uuencoded file pulled from the ABP FAQ:

begin 666 bogus.file
MLEHHWHURHUH %$^4653%#$#&^%$$46^%#^%)LKDUHEWFHIUG^$^#DJIUTE&F
M&#H:FNP(ENER(*HNFUHDG(&#&B#HY@#(*@YNUF(&$HU$HF(YSAUHIRY(&YHU
#(*NUFE(YHD7H
`
end

This shows the basics of a uuencoded file. The first line consists of the word begin, the permissions for the file, and the name of the file. The word begin tells the uudecoder where to start decoding the picture, and should always be lower case. The 666 refers to the file permissions of the file, which is usually somewhere between 600 and 777, and is not usually important. The last part of the first line is the name that the file will be when you finish decoding it, in this case, bogus.file.

The next four lines are the actual data. It should always be all upper case letters, numbers, and punctuation. The last line tells the decoder when to end uudecoding.

Why are all the uuencoded files split up into multiple parts?

Some newsreaders on some systems can only handle messages up to 64K, or they will erase the end of the message. While this is becoming less of a problem every year, there is still enough of them out there to cause people to take the nice route and split their messages up so no single part is longer than that. This makes decoding the files a little harder, especially if you do it manually, but it need to be done.

How do I Uudecode a file from the Usenet?

The traditional (and long) way is to use the program called uudecode, which is available on most Unix systems. Using this method, you have to save all the parts to a single file, strip out everything except the begin line, the data itself, and the end line, and then put it through the uudecode program. This is a pain in the ass, and lucky for us there are better ways to do it now.

'Smart decoders' are decoders where you can save all the parts to a single file, and it will strip out the header and misc information for you, and then decode it. These one step programs are the standard now, and make decoding a breeze.

Most Unix Newsreaders now have smart decoders built in. Nn, Rn, Trn, and Tin all have these included in the program, and it's a simple matter to see, get, and uudecode files, without even leaving your newsreader. Click on the links above to get instructions for these newsreaders, or I make these available in other ways. A new generation of smart uudecoders are becoming popular now, and these are multiple part smart decoders, Unpost being the most popular and widely distributed of these. With Unpost, you can save all the parts of all the posts that you want to decode to a single file, and do all the decoding in one shot automatically, much faster then you could any other way. This is the easiest way to decode many files at the same time, and can reduce the amount of time you spend decoding pics to a tenth of what it would be otherwise (depending on how many you are decoding). With unpost, you can even read all the posts right off the news spool, so you don't even have to load a newsreader at all. Unpost will work on Dos machines as well. If you want to decode pics via Windows or another platform, I suggest looking in the ABP faq.

OK, so I have decoded the file, what do I do now?

Well, you have to get the file to your home machine. This varies greatly depending on how you access the Internet. If you have a slip line or access the Inet through America On Line, it might be on your system as soon as you decode it. For most users though, who access the Internet through dial-up lines to a Unix shell account, the decoded file will be on the Unix hard drive, in the $HOME or $HOME/News directory. You can do a Zmodem download to get file to your home computer with the 'sz' command. If you wanted to download the bogus.file example above, you would type: sz bogus.file. After you do that, you might have to start the download manually on your home computer as well, although a lot of communication programs will do it for you. Look in the docs of your communication program for more info on how to do that.

Great, so I did all that and I have this Gif or Jpg picture siting on my hard drive, how do I look at it?

You need a viewing program. There are quite a number of viewing programs out there, both shareware and commercial, for all computers. Look at the alt.binaries.pictures FAQ for your choices. There are too many to really go over in the small document. The ABP faq is very well done and extensive, and should be looked at by anyone with an interest in pictures of any kind.


More of my graphics information.


I have written several FAQs on how to decode pics, and am making several other important FAQs available easily. You can get any of these FAQs from my ftp site (ftp to ftp.netcom.com:/pub/ha/hagie/faq/), via WWW below, or through e-mail by mailing me with a certain subject headers. The correct subjects and the faqs available are all below:

SubjectInformation
send helpThe list of all current FAQs.
send tin faqHelp with decoding Usenet binaries automatically with Tin.
send rn faqHelp with decoding Usenet binaries with Rn.
send trn faqHelp with decoding Usenet binaries with Trn faq. (same as Rn)
send nn faqHelp with decoding Usenet binaries with Nn faq.
send aol faqHelp with decoding Usenet binaries with the AOL reader.
send decode faqThe text version of this document.
send abp faqThe complete alt.binaries.pictures FAQ. Very informative.
send etiq faqBasic guidelines for Net-Etiquette. A must read.

Send mail to hagie@netcom.com with the subject line or body of the message one of the above. If you want to send me mail with other questions, avoid using any of the above send lines.


Other interesting Graphics links


The Alt.Binaries.Pictures Faq, a list of dozens of picture utilities.

WWW Graphics web page.

Unpost, a multi-part smart decoder for Unix and Dos.

Dos UUencoding and decoding software, plus some very good information about UUencoding.

Go to Scott's Homepage


Scott Hagie, hagie@netcom.com
October 26, 1995