\
special
commands supplied by the driver you’re using.
You need therefore to tell the package which driver to you’re using
(in the same way that you need to tell the graphics
package); the list of available drivers is pretty
wide, but does not include dvipdfm. The package comes with
a shell script chbar.sh (for use on Unix machines) that
will compare two documents and generate a third which is marked-up
with changebar macros to highlight changes.
The shareware WinEDT editor has a macro that will generate
changebar (or other) macros to show differences from an
earlier version of your file, stored in an RCS-controlled
repository — see
http://www.winedt.org/Macros/LaTeX/RCSdiff.php
The vertbars package uses the techniques of the
lineno package (which it loads, so the lineno
itself must be installed); it’s thus the smallest of the packages for
change bar marking, since it leaves all the trickery to another
package. Vertbars defines a vertbar
environment to create changebars.
The framed package is
another that provides bars as a side-effect of other desirable
functionality: its leftbar
environment is simply a
stripped-down frame (note, though, that the environment makes a
separate paragraph of its contents, so it is best used when the
convention is to mark a whole changed paragraph.
Finally, the memoir class allows marginal editorial comments,
which you can obviously use to delimit areas of changed text.
An even more comprehensive way to keep track of changes is employed by
some word-processors — to produce a document that embodies both
“old” and “new” versions.
To this end, the package changes allows the user to manually
markup changes of text, such as additions, deletions, or replacements.
Changed text is shown in a different colour; deleted text is crossed
out. The package allows you to define additional authors and their
associated colour; it also allows you to define a markup for authors
or annotations. The documentation (very clearly) demonstrates how the
various functions work.
The Perl script latexdiff may also be used to
generate such markup for LaTeX documents; you feed it the two
documents, and it produces a new LaTeX document in which the
changes are very visible. An example of the output is embedded in the
documentation,
latexdiff-man.pdf
(part of the distribution).
A rudimentary revision facility is provided by another
Perl script, latexrevise, which accepts or rejects
all changes. Manual editing of the difference file can be used to
accept or reject selected changes only.
This question on the Web: http://www.tex.ac.uk/cgi-bin/texfaq2html?label=changebars