Hello Gary,
address@hidden wrote:
I'm a Free Software noobie and probably have no idea what this is, but
it seems legit! :D Do you think you could explain it to me in like
layman's terms? :)
Welcome to the world of free(dom) software. Bruce put a very short
summary that answers your question in his announcement message.
Bruce Korb wrote:
GNU sharutils consists of two pairs of utilities: shar and unshar, and
uuencode and uudecode. "shar" makes so-called shell archives out of
many files, preparing them for transmission by electronic mail
services (converting binary data to ascii representations, breaking
the text into multiple shar scripts, etc.). "unshar" is the safe way
to extract and reassemble the original files. It will automatically
strip off the mail headers and other introductory text.
Even though email isn't a file transfer protocol and really shouldn't
be used as such just the same we have all used email to send files
anyway. (We shouldn't use 'cat file' to view a file either but we do
that all of the time too and accept the consequences if the file isn't
small enough or if it contains nasty escape sequences that kill our
terminal.) If the total size is small enough to go through email then
it works. But email has traditionally had 7-bit data character
limitations. And mailers will munge the content. It is hard to send
verbatim files through the email.
The shar program makes a "shell-archive" of 8-bit binary data into a
7-bit cleanly wrapped text file. This file can then be viewed with
text browsers and emailed through text mail. Traditionally we would
take a binary file, shar it, then email it to another who would unshar
it to receive the original binary file.
A shell archive is a shell script program. It is a self-extracting
script program that extracts itself into the files that were archived
within it. It is portable across many different Unix-like systems.
It's pretty cool!
"uuencode" and "uudecode" are programs that convert binary files into
ascii text so that the original data can pass through the email system
without having intermediate hosts "fixing" the files en route.
The "uu" parts of those names show they were associated with the uucp
unix-unix-copy programs. In the old days before networking the only
communication path was by modem line. One computer would call up
another computer. You could uucp a file from one computer to another
associated computer. The uucp program worked great for connected
systems. But what about email across several systems? That was where
uuencode and uudecode came into use. They are similar to shar and
unshar but more specific. When posting binary files to newsgroups it
was at one time typical to uuencode the binary file and post the
uuencoded version to news. The newsgroups then copied the files from
system to system using uucp. If you don't know what they are then you
probably don't need them.
These days perhaps the most active use of uudecode is to unpack old
archived postings to usenet that are still available. Or to unpack
other archived file. Files uuencoded are easily identified by the
uuencode header line in the file and the files are always viewable
because they are text files.
These days for the most part all data transfer is done 8-bit clean and
therefore does not need any of this wrapping and encoding. We would
simply use http or ftp or rsync or other binary transfer protocol and
simply copy the file around directly.
Email still needs it for its own use however. Email uses 'base64'
encoding. Base64 encoding is slightly different from the encoding
used by shar. It is incrementally more compact. But the MIME encoded
base64 encoding is very similar in use and concept.
This is a bug fix release for version 4.15 of sharutils
Even though these are venerable old tools and perhaps see less use
these days the programs are useful to have for the specific cases
where they are still used. Operating systems and environments change
slightly. It is useful to update the build environment for them.
Other small changes. Bruce has been maintaining these for years and
we thank him for doing so. I am still happily using sharutils. I
used them recently to unpack an archive of nettrek just the other day.
Bob