File README.SUSE of Package less
the 'less' application, thanks to its preprocessor, is able to show even binary
formats using calls to external commands. Since not every user finds this
feature plausible, you have the opportunity to customize behavior of 'less'
using the environment variable LESS_ADVANCED_PREPROCESSOR. By default, it's set
to "no" in /etc/profile -- thus if you require less to handle binary formats,
set this in your startup scripts:
Remark for experienced users:
If you had already set this switch and want to temporarily override it, you can
force 'less' to read a file from its standard input instead, e.g.:
less < dumb.ps
will show the source PostScript, and not the "rendered" result.