LIFE(6L) — UNIX Programmer’s Manual

NAME

life − play the game of life

SYNOPSIS

life [-r]

DESCRIPTION

Life is a pattern generating game set up for interactive use on a video terminal. The way it operates is: You use a series of commands to set up a pattern on the screen then let it generate further patterns from that pattern.

The algorithm used is: For each square in the matrix, look at it and its eight adjacent neighbors. If the present square is not occupied and exactly three of its neighbor squares are occupied, then that square will be occupied in the next pattern. If the present square is occupied and two or three of its neighbor squares are occupied, then that square will be occupied in the next pattern. Otherwise, the present square will not be occupied in the next pattern.

The edges of the screen are normally treated as an unoccupied void. If you specify the −r option on the command line, the screen is treated as a sphere; that is, the top and bottom lines are considered adjacent and the left and right columns are considered adjacent.

The pattern generation number and the number of occupied squares are displayed in the lower left hand corner.

Below is a list of commands available to the user. A # stands for any number. A ^ followed by a capital letter represents a control character.

#,#a Add a block of elements. The first number specifies the horizontal width. The second number specifies the vertical width. If a number is not specified, the default is 1.

#c Step through the next # patterns. If no number is specified, step forever. The operation can be aborted by typing rubout (delete).

#,#d Delete a block of elements. The first number specifies the horizontal width. The second number specifies the vertical width. If a number is not specified, the default is 1.

#f Generate a little flier at the present location. The number (modulo 8) determines the direction.

#,#g Move to absolute screen location. The first number specifies the horizontal location. The second number specifies the vertical location. If a number is not specified, the default is 0.

#h Move left # steps. If no number is specified, the default is 1.

#j Move down # steps. The default is 1.

#k Move up # steps. The default is 1.

#l Move right # steps. The default is 1.

#n Step through the next # patterns. If no number is specified, generate the next pattern. The operation can be aborted by typing rubout (delete).

p Put the last yanked or deleted block at the present location.

q Quit.

w Toggle the wrap-around mode.

#,#y Yank a block of elements. The first number specifies the horizontal width. The second number specifies the vertical width. If a number is not specified, the default is 1.

C Clear the pattern.

#F Generate a big flier at the present location. The number (modulo 8) determines the direction.

#H Move to the left margin.

#J Move to the bottom margin.

#K Move to the top margin.

#L Move to the right margin.

#R Generate a random field of density # percent.

#^H Move left # steps. If no number is specified, the default is 1.

#^J Move down # steps. The default is 1.

#^K Move up # steps. The default is 1.

#^L Move right # steps. The default is 1.

^R Redraw the screen. This is used for those occasions when the terminal screws up.

. Repeat the last add (a) or delete (d) operation.

; Repeat the last move (h, j, k, l) operation.

AUTHOR

Asa Romberger

BUGS

The following features are planned but not implemented:

#,#S Save the selected area in a file.

R Restore from a file.

m Generate a macro command.

! Shell escape.

e Edit a file.

i Input commands from a file.