NAME
hp — handle special functions of HP2640 and HP2621-series terminals
DESCRIPTION
hp
supports special functions of the Hewlett-Packard
HP
2640 and
HP
2621 series of terminals,
with the primary purpose of producing accurate representations of most
nroff
output.
A typical use is:
Regardless of the hardware options on a given terminal,
hp
tries to do sensible things with underlining and reverse line-feeds.
If the terminal has the ``display enhancements'' feature,
subscripts and superscripts can be indicated in distinct ways.
If it has the ``mathematical-symbol'' feature,
Greek and other special characters can be displayed.
Options
hp
recognizes the following options:
- -e
Specify that your terminal has the ``display enhancements'' feature,
to make maximal use of the added display modes.
Overstruck characters are presented in the Underline mode.
Superscripts are shown in Half-bright mode,
and subscripts in Half-bright, Underlined mode.
If this flag is omitted,
hp
assumes that your terminal lacks the ``display enhancements'' feature.
In this case, all overstruck characters, subscripts, and superscripts
are displayed in Inverse Video mode; that is, dark-on-light,
rather than light-on-dark.
- -m
Request minimization of output by removing new-lines.
Any contiguous sequence of 3 or more new-lines
is converted into a sequence of only 2 new-lines;
that is, any number of successive blank lines
produces only a single blank output line.
This allows you to retain more actual text on the screen.
DIAGNOSTICS
- line too long
The representation of a line exceeds 1,024 characters.
RETURN VALUE
hp
returns zero for normal termination, and 2 for all errors.
WARNINGS
An ``overstriking sequence'' is defined
as a printing character followed by a backspace
followed by another printing character.
In such sequences, if either printing character is an underscore,
the other printing character is shown underlined or in Inverse Video;
otherwise, only the first printing character is shown
(again, underlined or in Inverse Video).
Nothing special is done if a backspace is adjacent to an
ASCII
control character.
Sequences of control characters (e.g., reverse line-feeds, backspaces)
can make text ``disappear''; in particular, tables generated by
tbl
that contain vertical lines will often be missing the lines of text
that contain the ``foot'' of a vertical line,
unless the input to
hp
is piped through
col
(see
col(1)).
Although some terminals do support numerical superscript characters,
no attempt is made to display them.
