window(1)

NAME

window - window environment

SYNOPSIS

window [-t] [-f] [-d] [-e escape-char] [-c command]

DESCRIPTION

The window utility implements a window environment on ASCII

terminals.

A window is a rectangular portion of the physical terminal

screen associated with a set of processes. Its size and position can be

changed by
the user at any time. Processes communicate with their win

dow in the
same way they normally interact with a terminal-through

their standard
input, output, and diagnostic file descriptors. The window

program handles the details of redirecting input and output to and from

the windows.
At any one time, only one window can receive input from the

keyboard, but
all windows can simultaneously send output to the display.

When window starts up, the commands (see long commands be

low) contained
in the file .windowrc in the user's home directory are exe

cuted. If it
does not exist, two equal sized windows spanning the termi

nal screen are
created by default.

The command line options are

-t Turn on terse mode (see terse command below).

-f Fast. Do not perform any startup action.

-d Ignore .windowrc and create the two default win

dows instead.

-e escape-char

Set the escape character to escape-char.

Escape-char can be
a single character, or in the form ^X where X is

any character, meaning control-X.

-c command Execute the string command as a long command

(see below)

before doing anything else.

Windows can overlap and are framed as necessary. Each win

dow is named by
one of the digits ``1'' to ``9''. This one-character iden

tifier, as well
as a user definable label string, are displayed with the

window on the
top edge of its frame. A window can be designated to be in

the
foreground, in which case it will always be on top of all

normal, nonforeground windows, and can be covered only by other fore

ground windows.
A window need not be completely within the edges of the ter

minal screen.
Thus a large window (possibly larger than the screen) may be

positioned
to show only a portion of its full size.

Each window has a cursor and a set of control functions.

Most intelligent terminal operations such as line and character deletion

and insertion are supported. Display modes such as underlining and

reverse video
are available if they are supported by the terminal. In ad

dition, similar to terminals with multiple pages of memory, each window

has a text
buffer which can have more lines than the window itself.

Process Environment

With each newly created window, a shell program is spawned

with its process environment tailored to that window. Its standard in

put, output,
and diagnostic file descriptors are bound to one end of ei

ther a pseudoterminal (see pty(4)) or a UNIX domain socket (see socket

pair(2)). If a
pseudo-terminal is used, then its special characters and

modes (see
stty(1)) are copied from the physical terminal. A term

cap(5) entry tailored to this window is created and passed as environment

(see
environ(7)) variable TERMCAP. The termcap entry contains

the window's
size and characteristics as well as information from the

physical terminal, such as the existence of underline, reverse video, and

other display
modes, and the codes produced by the terminal's function

keys, if any.
In addition, the window size attributes of the pseudo-termi

nal are set to
reflect the size of this window, and updated whenever it is

changed by
the user. In particular, the editor vi(1) uses this infor

mation to
redraw its display.

Operation

During normal execution, window can be in one of two states:

conversation
mode and command mode. In conversation mode, the terminal's

real cursor
is placed at the cursor position of a particular win

dow--called the current window--and input from the keyboard is sent to the pro

cess in that
window. The current window is always on top of all other

windows, except
those in foreground. In addition, it is set apart by high

lighting its
identifier and label in reverse video.

Typing window's escape character (normally ^P) in conversa

tion mode
switches it into command mode. In command mode, the top

line of the terminal screen becomes the command prompt window, and window

interprets
input from the keyboard as commands to manipulate windows.

There are two types of commands: short commands are usually

one or two
key strokes; long commands are strings either typed by the

user in the
command window (see the ``:'' command below), or read from a

file (see
source below).

Short Commands

Below, # represents one of the digits ``1'' to ``9'' corre

sponding to the
windows 1 to 9. ^X means control-X, where X is any charac

ter. In particular, ^^ is control-^. Escape is the escape key, or ^[.

# Select window # as the current window and return to

conversation

mode.

%# Select window # but stay in command mode.

^^ Select the previous window and return to conversa

tion mode. This

is useful for toggling between two windows.

escape Return to conversation mode.

^P Return to conversation mode and write ^P to the cur

rent window.

Thus, typing two ^P's in conversation mode sends one

to the current window. If the window escape is changed to

some other character, that character takes the place of ^P here.

? List a short summary of commands.

^L Refresh the screen.

q Exit window. Confirmation is requested.

^Z Suspend window.

w Create a new window. The user is prompted for the

positions of

the upper left and lower right corners of the win

dow. The cursor
is placed on the screen and the keys ``h'', ``j'',

``k'', and
``l'' move the cursor left, down, up, and right, re

spectively.
The keys ``H'', ``J'', ``K'', and ``L'' move the

cursor to the
respective limits of the screen. Typing a number

before the
movement keys repeats the movement that number of

times. Return
enters the cursor position as the upper left corner

of the window. The lower right corner is entered in the same

manner. During this process, the placement of the new window is

indicated by
a rectangular box drawn on the screen, corresponding

to where the
new window will be framed. Typing escape at any

point cancels
this command.

This window becomes the current window, and is given

the first
available ID. The default buffer size is used (see

default_nline
command below).

Only fully visible windows can be created this way.

c# Close window #. The process in the window is sent

the hangup

signal (see kill(1)). The csh(1) utility should

handle this signal correctly and cause no problems.

m# Move window # to another location. A box in the

shape of the

window is drawn on the screen to indicate the new

position of the
window, and the same keys as those for the w command

are used to
position the box. The window can be moved partially

off-screen.

M# Move window # to its previous position.

s# Change the size of window #. The user is prompted

to enter the

new lower right corner of the window. A box is

drawn to indicate
the new window size. The same keys used in w and m

are used to
enter the position.

S# Change window # to its previous size.

^Y Scroll the current window up by one line.

^E Scroll the current window down by one line.

^U Scroll the current window up by half the window

size.

^D Scroll the current window down by half the window

size.

^B Scroll the current window up by the full window

size.

^F Scroll the current window down by the full window

size.

h Move the cursor of the current window left by one

column.

j Move the cursor of the current window down by one

line.

k Move the cursor of the current window up by one

line.

l Move the cursor of the current window right by one

column.

y Yank. The user is prompted to enter two points

within the cur

rent window. Then the content of the current window

between
those two points is saved in the yank buffer.

p Put. The content of the yank buffer is written to

the current

window as input.

^S Stop output in the current window.

^Q Start output in the current window.

: Enter a line to be executed as long commands. Nor

mal line edit

ing characters (erase character, erase word, erase

line) are supported.

Long Commands

Long commands are a sequence of statements parsed much like

a programming
language, with a syntax similar to that of C. Numeric and

string expressions and variables are supported, as well as conditional

statements.

There are two data types: string and number. A string is a

sequence of
letters or digits beginning with a letter. ``_'' and ``.''

are considered letters. Alternately, non-alphanumeric characters can

be included
in strings by quoting them in ``"'' or escaping them with

``´'. In
addition, the ``´' sequences of C are supported, both inside

and outside '' a carriage return).
quotes (e.g., ``0' is a new line, `` For example, these are legal strings: abcde01234, "&#$^*&#",

ab"$#"cd, ab "/usr/ucb/window".

A number is an integer value in one of three forms: a deci

mal number, an
octal number preceded by ``0'', or a hexadecimal number pre

ceded by
``0x'' or ``0X''. The natural machine integer size is used

(i.e., the
signed integer type of the C compiler). As in C, a non-zero

number represents a boolean true.

The character ``#'' begins a comment which terminates at the

end of the
line.

A statement is either a conditional or an expression. Ex

pression statements are terminated with a new line or ``;''. To continue

an expression
on the next line, terminate the first line with ``´'.

Conditional Statement

The window utility has a single control structure: the fully

bracketed if
statement in the form

if <expr> then
<statement>
...
elsif <expr> then
<statement>
...
else
<statement>
...
endif

The else and elsif parts are optional, and the latter can be

repeated any
number of times. <Expr> must be numeric.

Expressions

Expressions in window are similar to those in the C lan

guage, with most C
operators supported on numeric operands. In addition, some

are overloaded to operate on strings.

When an expression is used as a statement, its value is dis

carded after
evaluation. Therefore, only expressions with side effects

(assignments
and function calls) are useful as statements.

Single valued (no arrays) variables are supported, of both

numeric and
string values. Some variables are predefined. They are

listed below.

The operators in order of increasing precedence:

<expr1> = <expr2>

Assignment. The variable of name <expr1>, which

must be
string valued, is assigned the result of

<expr2>. Returns
the value of <expr2>.

<expr1> ? <expr2> : <expr3>

Returns the value of <expr2> if <expr1> evalu

ates true (nonzero numeric value); returns the value of

<expr3> otherwise.
Only one of <expr2> and <expr3> is evaluated.

<Expr1> must
be numeric.

<expr1> || <expr2>

Logical or. Numeric values only. Short circuit

evaluation
is supported (i.e., if <expr1> evaluates true,

then <expr2>
is not evaluated).

<expr1> && <expr2>

Logical and with short circuit evaluation. Nu

meric values
only.

<expr1> | <expr2>

Bitwise or. Numeric values only.

<expr1> ^ <expr2>

Bitwise exclusive or. Numeric values only.

<expr1> & <expr2>

Bitwise and. Numeric values only.

<expr1> == <expr2>, <expr1> != <expr2>

Comparison (equal and not equal, respectively).

The boolean
result (either 1 or 0) of the comparison is re

turned. The
operands can be numeric or string valued. One

string operand
forces the other to be converted to a string in

necessary.

<expr1> < <expr2>, <expr1> > <expr2>, <expr1> <= <expr2>,

Less than, greater than, less than or equal to,

greater than
or equal to. Both numeric and string values,

with automatic
conversion as above.

<expr1> << <expr2>, <expr1> >> <expr2>

If both operands are numbers, <expr1> is bit

shifted left (or
right) by <expr2> bits. If <expr1> is a string,

then its
first (or last) <expr2> characters are returns

(if <expr2> is
also a string, then its length is used in place

of its
value).

<expr1> + <expr2>, <expr1> - <expr2>

Addition and subtraction on numbers. For ``+'',

if one argument is a string, then the other is converted to

a string,
and the result is the concatenation of the two

strings.

<expr1> * <expr2>, <expr1> / <expr2>, <expr1> % <expr2>

Multiplication, division, modulo. Numbers only.

-<expr>, ~<expr>, !<expr>, $<expr>, $?<expr>

The first three are unary minus, bitwise comple

ment and logical complement on numbers only. The operator,

``$'', takes
<expr> and returns the value of the variable of

that name.
If <expr> is numeric with value n and it appears

within an
alias macro (see below), then it refers to the

nth argument
of the alias invocation. ``$?'' tests for the

existence of
the variable <expr>, and returns 1 if it exists

or 0 otherwise.

<expr>(<arglist>)

Function call. <Expr> must be a string that is

the unique
prefix of the name of a builtin window function

or the full
name of a user defined alias macro. In the case

of a builtin
function, <arglist> can be in one of two forms:

<expr1>, <expr2>, ...
argname1 = <expr1>, argname2 = <expr2>,

The two forms can in fact be intermixed, but the

result is
unpredictable. Most arguments can be omitted;

default values
will be supplied for them. The argnames can be

unique prefixes of the argument names. The commas sepa

rating arguments
are used only to disambiguate, and can usually

be omitted.

Only the first argument form is valid for user

defined
aliases. Aliases are defined using the alias

builtin function (see below). Arguments are accessed via a

variant of
the variable mechanism (see ``$'' operator

above).

Most functions return value, but some are used

for side
effect only and so must be used as statements.

When a function or an alias is used as a statement, the

parentheses surrounding the argument list may be omitted.

Aliases return no
value.

Builtin Functions

The arguments are listed by name in their natural order.

Optional arguments are in square brackets `[]'. Arguments that have no

names are in
angle brackets `<>'. An argument meant to be a boolean flag

(often named
flag) can be one of on, off, yes, no, true, or false, with

obvious meanings, or it can be a numeric expression, in which case a

non-zero value
is true.

alias([<string>], [<string-list>])

If no argument is given, all currently defined

alias macros
are listed. Otherwise, <string> is defined as

an alias, with
expansion <string-list >>. The previous defini

tion of
<string>, if any, is returned. Default for

<string-list> is
no change.

close(<window-list>)

Close the windows specified in <window-list>.

If
<window-list> is the word all, than all windows

are closed.
No value is returned.

cursormodes([modes])

Set the window cursor to modes. Modes is the

bitwise or of
the mode bits defined as the variables m_ul (un

derline),
m_rev (reverse video), m_blk (blinking), and

m_grp (graphics,
terminal dependent). Return value is the previ

ous modes.
Default is no change. For example, cur

sor($m_rev$m_blk) sets
the window cursors to blinking reverse video.

default_nline([nline])

Set the default buffer size to nline. Initial

ly, it is 48
lines. Returns the old default buffer size.

Default is no
change. Using a very large buffer can slow the

program down
considerably.

default_shell([<string-list>])

Set the default window shell program to

<string-list>.
Returns the first string in the old shell set

ting. Default
is no change. Initially, the default shell is

taken from the
environment variable SHELL.

default_smooth([flag])

Set the default value of the smooth argument to

the command
window (see below). The argument is a boolean

flag (one of
on, off, yes, no, true, false, or a number, as

described
above). Default is no change. The old value

(as a number)
is returned. The initial value is 1 (true).

echo([window], [<string-list>])

Write the list of strings, <string-list>, to

window, separated by spaces and terminated with a new line.

The strings
are only displayed in the window, the processes

in the window
are not involved (see write below). No value is

returned.
Default is the current window.

escape([escapec])

Set the escape character to escape-char. Re

turns the old
escape character as a one-character string. De

fault is no
change. Escapec can be a string of a single

character, or in
the form -^X, meaning control-X.

foreground([window], [flag])

Move window in or out of foreground. Flag is a

boolean
value. The old foreground flag is returned.

Default for
window is the current window, default for flag

is no change.

label([window], [label])

Set the label of window to label. Returns the

old label as a
string. Default for window is the current win

dow, default
for label is no change. To turn off a label,

set it to an
empty string ("").

list() No arguments. List the identifiers and labels

of all win

dows. No value is returned.

select([window])

Make window the current window. The previous

current window
is returned. Default is no change.

source(filename)

Read and execute the long commands in filename.

Returns -1
if the file cannot be read, 0 otherwise.

terse([flag])

Set terse mode to flag. In terse mode, the com

mand window
stays hidden even in command mode, and errors

are reported by
sounding the terminal's bell. Flag can take on

the same values as in foreground above. Returns the old

terse flag.
Default is no change.

unalias(alias)

Undefine alias. Returns -1 if alias does not

exist, 0 otherwise.

unset(variable)

Undefine variable. Returns -1 if variable does

not exist, 0
otherwise.

variables()

No arguments. List all variables. No value is

returned.

window([row], [column], [nrow], [ncol], [nline], [label],

[pty], [frame],

[mapnl], [keepopen], [smooth], [shell]). Open a window with upper left corner at row,

column and size
nrow, ncol. If nline is specified, then that

many lines are
allocated for the text buffer. Otherwise, the

default buffer
size is used. Default values for row, column,

nrow, and ncol
are, respectively, the upper, left-most, lower,

or right-most
extremes of the screen. Label is the label

string. Frame,
pty, and mapnl are flag values interpreted in

the same way as
the argument to foreground (see above); they

mean, respectively, put a frame around this window (default

true), allocate pseudo-terminal for this window rather than

socketpair
(default true), and map new line characters in

this window to
carriage return and line feed (default true if

socketpair is
used, false otherwise). Normally, a window is

automatically
closed when its process exits. Setting keepopen

to true
(default false) prevents this action. When

smooth is true,
the screen is updated more frequently (for this

window) to
produce a more terminal-like behavior. The de

fault value of
smooth is set by the default_smooth command (see

above).
Shell is a list of strings that will be used as

the shell
program to place in the window (default is the

program specified by default_shell, see above). The created

window's
identifier is returned as a number.

write([window], [<string-list>])

Send the list of strings, <string-list>, to

window, separated
by spaces but not terminated with a new line.

The strings
are actually given to the window as input. No

value is
returned. Default is the current window.

Predefined Variables

These variables are for information only. Redefining them

does not
affect the internal operation of window.

baud The baud rate as a number between 50 and 38400.

modes The display modes (reverse video, underline, blink

ing, graphics)

supported by the physical terminal. The value of

modes is the
bitwise or of some of the one bit values, m_blk,

m_grp, m_rev, and
m_ul (see below). These values are useful in setting

the window
cursors' modes (see cursormodes above).

m_blk The blinking mode bit.

m_grp The graphics mode bit (not very useful).

m_rev The reverse video mode bit.

m_ul The underline mode bit.

ncol The number of columns on the physical screen.

nrow The number of rows on the physical screen.

term The terminal type. The standard name, found in the

second name

field of the terminal's TERMCAP entry, is used.

ENVIRONMENT

The window utility utilizes these environment variables:

HOME, SHELL,
TERM, TERMCAP, WINDOW_ID.

FILES

~/.windowrc startup command file.
/dev/[pt]ty[pq]? pseudo-terminal devices.

DIAGNOSTICS

Should be self explanatory.

HISTORY

The window command appeared in 4.3BSD.

BSD December 30, 1993

BSD