FROTZ(6)

NAME
dfrotz - interpreter for Infocom and other Z-Machine games (dumb interface)

SYNOPSIS
dfrotz [options] file

DESCRIPTION
Frotz is a Z-Machine interpreter. The Z-machine is a virtual machine designed by Infocom to run all of their text adventures. It went through multiple revisions during the lifetime of the company, and two further revisions (V7 and V8) were created by Graham Nelson after the company's demise. The specification is now quite well documented; this version of Frotz supports version 1.0.

This version of Frotz fully supports all these versions of the Z-Machine except for version 6. Version 6 is semi-supported by displaying the outlines of V6 graphics with the picture number in the bottom-right corner.

This manpage is for Frotz with the dumb interface. Neither sound-effects nor colors are supported.

OPTIONS

-a  Watch attribute setting. Setting and clearing of attributes on objects will be noted in debugging messages.

-A  Watch attribute testing. Every time the z-machine tests an attribute value, the test and the result will be reported.

-h N
    Screen height. Every N lines, a MORE prompt will be printed. Use of the -m option renders this option moot.

-i  Ignore fatal errors. If a Z-Machine interpreter encounters a zcode error such as division-by-zero or addressing an illegal object, the proper response is to abort execution. This is done because the zcode program doesn't have a clear idea of what is going on. There are some games out there that cause fatal errors because the authors were careless and used an interpreter that didn't properly check for errors. This option is intended to get around such bugs, but be warned that Strange Things may happen if fatal errors are not caught.

-m  Turn off MORE prompts. This can be desirable when using a printing terminal.

-o  Watch object movement. This option enables debugging messages from the interpreter which describe the moving of objects in the object tree.

-O  Watch object location. These debugging messages detail the locations of objects in the object tree.

-p  Plain ASCII output only. This inhibits the output of accented letters and other characters from the Latin-1 character set, replacing them with reasonable alternatives. This may be necessary on devices lacking these characters.

-P  Alter the piracy opcode. The piracy opcode was never used by Infocom. This switch is really only useful for those who like to toy around with Z-code.

-R \xxx
    Set runtime options. This option may be used repeatedly.

-s N
    Set the random number seed value. The given seed value is used as the initial seed value on every restart. This is helpful for testing games like Curses which make random decisions before the first input (such that the hot key Alt-S does not really help).

-S N
    Set the transcript width. By default your transscript files are formatted to a width of 80 columns per line, regardless of the current screen width. This switch allows you to change this setting. In particular, use -S 0 to deactivate automatic line splitting in transscript files.

-t  Sets the z-machine's Tandy bit, which may affect the behavior of certain Infocom games. For example, Zork I pretends not to have sequels, and Witness has its language toned down.

-u N
    Sets the number of slots available for Frotz's multiple undo hotkey (see below). This defaults to twenty, which should be sufficient for most purposes. Setting too high a number here may be dangerous on machines with limited memory.

-w N
    Manually sets the screen width. This should not be necessary except in special circumstances.

-x  Expand the abbreviations "g", "x", and "z" to "again", "examine", and "wait". This switch is for use iwth old Infocom games that lack these common abbreviations which were introduced in later games. Use it with caution: A few games might use "g", "x" or "z" for different purposes.

-Z N
    Error checking mode.
    0 = don't report errors.
    1 = report first instance of an error.
    2 = report all errors.
    3 = exit after any error.
    Default is 1 (report first instance of an error).

CONFIGURATION
Unline it's curses-using sibling, dfrotz does not use configuration files. All configuration is done on the command line or while dfrotz is running.

  General Commands

\help
    Show help message.

\set
    Show the current values of runtime settings.

\s  Show the current contents of the whole screen.

\d  Discard the part of the input before the cursor.

\wN Advance clock N/10 seconds, possibly causing the current and subsequent inputs to timeout.

\w  Advance clock by the amount of real time since this input started (times the current speed factor).

\t  Advance clock just enough to timeout the current input

  Reverse-Video Display Method Settings

\rn none

\rc CAPS

\rd doublestrike

\ru underline

  Output Compression Settings

\cn none: show whole screen before every input.

\cm max: show only lines that have new nonblank characters.

\cs spans: like max, but emit a blank line between each span of screen lines shown.

\chN
    Hide top N lines (orthogonal to above modes).

  Misc Settings

\sfX
    Set speed factor to X. (0 = never timeout automatically).

\mp Toggle use of MORE prompts

\ln Toggle display of line numbers.

\lt Toggle display of the line type identification chars.

\vb Toggle visual bell.

\pb Toggle display of picture outline boxes.

(Toggle commands can be followed by a 1 or 0 to set value ON or OFF.)

  Character Escapes

\\  backslash

\#  backspace

\[  escape

\_  return

\<  cursor-left

\>  cursor-right

\^  cursor-up

\.  cursor-down

\1..\0
    f1..f10

\D..\X
    Standard Frotz hotkeys.

use \H (help) to see the list of hotkeys.

  Line Type Identification Characters

  Input lines (untimed)

>   A regular line-oriented input

)   A single-character input

}   A line input with some input before the cursor. Use \d to discard it.

  Input lines (timed)

T   A regular line-oriented input

t   A single-character input

D   A line input with some input before the cursor. Use \d to discard it.

  Output lines

]   Output line that contains the cursor.

.   A blank line emitted as part of span compression.

    (blank) Any other output line.

ENVIRONMENT
Unline it's curses-using sibling, dfrotz does not search any path for game files.

FURTHER INFORMATION

A git(1) repository of all versions of Unix Frotz back to 2.32 is available for public perusal here:
https://github.com/DavidGriffith/frotz/.

The bleeding edge of Frotz development may be followed there. A wiki summarising Frotz is also there at this URL:
https://github.com/DavidGriffith/frotz/wiki/

Source tarballs are available at the IF Archive or any of its many mirrors:
http://www.ifarchive.org/

Most distributions of Linux and BSD include Frotz in their package repositories.

CAVEATS

The Z Machine itself has trouble with the concept of resizing a terminal. It assumes that once the screen height and width are set, they will never change; even across saves. This made sense when 24x80 terminals were the norm and graphical user interfaces were mostly unknown. I'm fairly sure there's a way around this problem, but for now, don't resize an xterm in which frotz is running. Also, you should try to make sure the terminal on which you restore a saved game has the same dimensions as the one on which you saved the game.

This manpage is not intended to tell users HOW to play interactive fiction. Refer to the file HOW_TO_PLAY included in the Unix Frotz documentation or visit one of the following sites:
http://www.microheaven.com/ifguide/
http://www.brasslantern.org/beginners/
http://www.musicwords.net/if/how_to_play.htm

If you prefer a PDF file of how to play, here is one:
http://inform-fiction.org/I7Downloads/Examples/dm/IntroductionToIF.pdf

BUGS
This program has no bugs. no bugs. no bugs. no *WHAP* thank you. If you find one, please report it to the Github site referenced above in FURTHER INFORMATION.

AUTHORS
Frotz was written by Stefan Jokisch in 1995-7.
The Unix port was done by Galen Hazelwood.
The Unix port is currently maintained by David Griffith <dave@661.org>.

SEE ALSO
frotz(6) nitfol(6) rezrov(6) jzip(6) xzip(6) inform(1)