UNIX for Dummies Questions & Answers

Can anyone explain how .bun documents work?

It's seems like a beautifully simple concept as it uses only echo, sed and the Bourne shell's features.

When this plain text file is executed it yields several docs in pure troff (sed removes the "-" prefix to each line). I am guessing these represent the individual pages.

So is a .bun file just a HERE doc?

I'm still learning troff and so far I only know a few basic commands. I presume I'm supposed to convert these "pages" into a single postscript file. Is having the document in split into multiple pages like this easier for troff to process?

Anyway, here's an example:

Code:

# To unbundle, run this file
echo cdoc0
sed 's/.//' >cdoc0 <<'//GO.SYSIN DD cdoc0'
-.TL
-A Tour through the UNIX\(dg C Compiler
-.AU "MH 2C517 3770
-D. M. Ritchie
-.AI
-.MH
-.OK

...more troff commands and text...

//GO.SYSIN DD cdoc0
echo cdoc1
sed 's/.//' >cdoc1 <<'//GO.SYSIN DD cdoc1'

...troff commands and text...

//GO.SYSIN DD cdoc1
echo cdoc2
sed 's/.//' >cdoc2 <<'//GO.SYSIN DD cdoc2'

...troff commands and text...

//GO.SYSIN DD cdoc2
echo cdoc3
sed 's/.//' >cdoc3 <<'//GO.SYSIN DD cdoc3'

...troff commmands and text...

//GO.SYSIN DD cdoc3
echo cdoc4
sed 's/.//' >cdoc4 <<'//GO.SYSIN DD cdoc4'

...troff commands and text...

//GO.SYSIN DD cdoc4

...troff commands and text...

Cheers!

Those bits containing TROFF text etc. are "here documents". They allow you to conveniently redirect large amounts of almost-raw text from the script itself into a process, which makes it relatively easy to bundle it all together.

Code:

cat > outfile <<EOF
This "here document" was written by ${USER} at $(date)
...any number of lines of text not starting with EOF...
EOF

Note the ending EOF must start at the beginning of the line. EOF can also be any string as long as the starting and ending one match. Also note that substitutions are allowed, so if you want certain text to be literal( $ signs, and so forth) they must be escaped.

Here they are using sed to chop off the first character of every line. They've added dashes to the front of every line to guarantee that the here document won't end prematurely if someone feeds it just the right string to terminate it, i.e. "//GO.SYSIN DD cdoc1"

This file was probably generated by another script. I've seen this sort of thing done occasionally but haven't stumbled across the generator for them.

Note the Author: Dennis Ritchie

These things have been around forever, like SHAR files.

Hi.

I could not find bun at first because one web page, that of: Tim Goodwin, was not currently available as linked from Linux Online - Application: bun

I used the Wayback machine, and you can get bun from there:

bun - bundle many files together

The tar file contains almost 200 files, c source mostly.

However, I think shar is likely better (does MD% checksums, etc), and is likely available on / for most *nix systems, supported, etc. ... cheers, drl

A belated thanks for the responses.
It is interesting.
I notice than Plan 9 retained the bun program.