frotz - interpreter for Infocom and other Z-Machine games

frotz [options] file

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 port supports old-style sound effects through the OSS sound driver.

-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.

-b <colorname>

Sets the default background color. <colorname> corresponds to one of the Z-machine colors, which are as follows:

black red green yellow blue magenta cyan white

If color support is disabled or not available on your terminal, this option does nothing.

-c N

Sets the number of context lines used. By default, after a ``[MORE]'' prompt, and assuming there is enough output pending, Frotz will allow all the currently visible lines to scroll off the screen before prompting again. This switch specifies how many lines of text Frotz will hold over and display at the top of the next screen.

-d

Disable color.

-e

Enable sound. If you've disabled sound in a config file and want to hear sound effects, use this.

-f <colorname>

Sets the default foreground color. <colorname> corresponds to one of the Z-machine colors, which are as follows

black red green yellow blue magenta cyan white

If color support is disabled or is not available on your terminal, this option does nothing.

-F

Force color mode. If you've disabled color in a config file and want to Frotz to display colors, use this.

-h N

Manually sets the screen height. Though most curses libraries are intelligent enough to determine the current width from the terminal, it may sometimes be necessary to use this option to override the default.

-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.

-l N

Sets the left margin, for those who might have specific formatting needs.

-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.

-q

Quiet. Turns off sound effects. Useful when running Frotz on a remote machine and you don't want to bother whoever's near the console with weird noises.

-Q

No Quetzal. By default, Frotz uses the new Quetzal save format when you save your game. If for some reason you want to save and restore using the old Frotz format, use this flag.

-r N

Sets the right margin.

-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. Again, 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).

On startup, frotz will first check the system's frotz.conf then $HOME/.frotzrc for configuration information. The configuration file uses a simple

<variable> <whitespace> <value> syntax.

Color names may be any of the following:

black | red | green | blue | magenta | cyan | white

ascii on | off

Use plain ASCII only. Default is "off".

background <colorname>

Set background color. Default is terminal's default background color.

color yes | no

Use color text. Default is "yes" if supported.

errormode never | once | always | fatal

Set error reporting mode.

never Don't report any errors except for fatal ones.

once Report only the first instance of an error.

always Report every instance of an error.

fatal Abort on any error, even non-fatal ones.

Default is "once".

expand_abb on | off

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

foreground <colorname>

Set foreground color. Default is terminal's default forground color.

ignore_fatal on | off

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.

Default is "off"

piracy on | off

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

quetzal on | off

Use Quetzal save format. Default is on. If for some reason you want to save or restore using the old Frotz format, set this to "off".

randseed <integer>

Set random number seed. Default comes from the Unix epoch.

sound on | off

Turn sound effects on or off. Default is "on".

tandy on | off

Set the machine's Tandy bit. This may affect the behavior of certain Infocom games. For example, Zork I pretends not to have sequels, and Witness has its language toned down. Default is "off".

undo_slots <integer>

Set number of undo slots. Default is 500.

zcode_path /path/to/zcode/files:/another/path

Set path to search for zcode game files. This is just like the $PATH environmental variable except that you can't put environmental variables in the path or use other shortcuts. For example, "$HOME/games/zcode" is illegal because the shell can't interpret that $HOME variable.

The following options are really only useful for weird terminals, weird curses libraries or if you want to force a certain look (like play in 40-column mode).

context_lines <integer>

Set the number of context lines used. By default, after a ``[MORE]'' prompt, and assuming there is enough output pending, frotz will allow all the currently visible lines to scroll off the screen before prompting again. This switch specifies how many lines of text frotz will hold over and display at the top of the next screen. Default is "0".

left_margin <integer>

Set the left margin. This is for those who might have special formatting needs.

right_margin <integer>

Set the right margin. This is for those who might have special formatting needs.

screen_height <integer>

Manually set screen height. Most curses libraries are intelligent enough to determine the current width of the terminal. You may need to use this option to override the default.

screen_width <integer>

Manually set screen width. Again, this should not be necessary except in special circumstances.

script_width <integer>

Set the transcript width. Default is 80 columns per line, regardless of the current screen width. This switch allows you to change this setting. You may set this to "0" to deactivate automatic line-splitting in transcript files.

The following options are mainly useful for debugging or cheating.

attrib_set on | off

Watch attribute setting. Setting and clearing of attributes on objects will be noted in debugging messages. Default is "off"

attrib_test on | off

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

obj_loc on | off

Watch object location. These debugging messages detail the locations of objects in the object tree. Default is "off".

obj_move on | off

Watch object movement. This option enables debugging messages from the interpreter which describe the movement of objects in the object tree. Default is "off".

If the ZCODE_PATH environmental variable is defined, frotz will search that path for game files. If that doesn't exist, INFOCOM_PATH will be searched.

Latest information on Unix Frotz is here:

http://www.cs.csubak.edu/~dgriffi/proj/frotz/

The latest release of Unix Frotz is here:

ftp://ftp.ifarchive.org/if-archive/infocom/interpreters/frotz/

See this website for a list of mirrors:

http://www.ifarchive.org

See this website for more information on Infocom past, present, and future; and where to get new Z-Machine games and the old ones by Infocom:

http://www.csd.uwo.ca/Infocom/

Frotz for other platforms:

http://www.geocities.com/SiliconValley/Heights/3222/frotz.html

In this Debian version, Frotz creates the directory $HOME/.infocom to place saved games into. The default name for saved games is $HOME/.infocom/<gamename>.sav, where <gamename> is the stem of the name of the game file.

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.

You can use a path like "/usr/local/games/zcode:$HOME/zcode" with $ZCODE_PATH or $INFOCOM_PATH because the shell will digest that $HOME variable for you before setting $ZCODE_PATH. While processing frotz.conf and $HOME/.frotzrc, a shell is not used. Therefore you cannot use environmental variables in the "zcodepath" option within the config files.

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.csd.uwo.ca/Infocom/faq.html

http://www.cs.csubak.edu/~dgriffi/proj/frotz/HOW_TO_PLAY

http://www.ifarchive.org

This program has no bugs. no bugs. no bugs. no *WHAP* thank you.

Frotz was written by Stefan Jokisch in 1995-7.

The Unix port was done by Galen Hazelwood.

Currently the Unix port is maintained by David Griffith.

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