window - window environment
window [ -t ] [ -f ] [ -d ] [ -e escape-char ] [ -c command ]
Window 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 com-
municate with their window 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 an 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.
Windows can overlap and are framed as necessary. Each window is named by one of the dig-
its ``1'' to ``9''. This one character identifier, as well as a user definable label
string, are displayed with the window on the top edge of its frame. A window can be des-
ignated to be in the foreground, in which case it will always be on top of all normal,
non-foreground windows, and can be covered only by other foreground windows. A window
need not be completely within the edges of the terminal screen. Thus a large window (pos-
sibly 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 opera-
tions 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
addition, similar to terminals with multiple pages of memory, each window has a text buf-
fer which can have more lines than the window itself.
When window starts up, the commands (see long commands below) contained in the file .win-
dowrc in the user's home directory are executed. If it does not exist, two equal sized
windows spanning the terminal screen are created by default.
The command line options are
-t Turn on terse mode (see terse command below).
-f Fast. Don't perform any startup action.
-d Ignore .windowrc and create the two default windows instead.
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.
Execute the string command as a long command (see below) before doing anything
With each newly created window, a shell program is spawned with its process environment
tailored to that window. Its standard input, output, and diagnostic file descriptors are
bound to one end of either a pseudo-terminal (pty (4)) or a UNIX domain socket (socketpair
(4)). If a pseudo-terminal is used, then its special characters and modes (see stty (1))
are copied from the physical terminal. A termcap (5) entry tailored to this window is
created and passed as environment (environ (5)) variable TERMCAP. The termcap entry con-
tains the window's size and characteristics as well as information from the physical ter-
minal, 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-terminal 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 informa-
tion to redraw its display.
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 window--called the current window--and input from the keyboard is sent to
the process 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 highlighting its identifier
and label in reverse video.
Typing window's escape character (normally ^P) in conversation mode switches it into com-
mand 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
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).
Below, # represents one of the digits ``1'' to ``9'' corresponding to the windows 1 to 9.
^X means control-X, where X is any character. 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 conversation mode. This is useful for
toggling between two windows.
escape Return to conversation mode.
^P Return to conversation mode and write ^P to the current 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 Redraw 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 window. The cursor is placed on the screen and the keys
``h'', ``j'', ``k'', and ``l'' move the cursor left, down, up, and right, respec-
tively. 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 move-
ment 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. Dur-
ing 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 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)). Csh (1) 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
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.
^S Stop output in the current window.
^Q Start output in the current window.
: Enter a line to be executed as long commands. Normal line editing characters
(erase character, erase word, erase line) are supported.
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 quotes (e.g., ``\n'' is a new line, ``\r'' a carriage return). For example, these
are legal strings: abcde01234, "&#$^*&#", ab"$#"cd, ab\$\#cd, "/usr/ucb/window".
A number is an integer value in one of three forms: a decimal number, an octal number pre-
ceded by ``0'', or a hexadecimal number preceded 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. Expression statements are termi-
nated with a new line or ``;''. To continue an expression on the next line, terminate the
first line with ``\''.
Window has a single control structure: the fully bracketed if statement in the form
if <expr> then
. . .
elsif <expr> then
. . .
. . .
The else and elsif parts are optional, and the latter can be repeated any number of times.
<Expr> must be numeric.
Expressions in window are similar to those in the C language, with most C operators sup-
ported on numeric operands. In addition, some are overloaded to operate on strings.
When an expression is used as a statement, its value is discarded after evaluation.
Therefore, only expressions with side effects (assignments and function calls) are useful
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> evaluates true (non-zero numeric value);
returns the value of <expr3> otherwise. Only one of <expr2> and <expr3> is evalu-
ated. <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. Numeric 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 returned. 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>, <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
<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
<expr1> * <expr2>, <expr1> / <expr2>, <expr1> % <expr2>
Multiplication, division, modulo. Numbers only.
-<expr>, ~<expr>, !<expr>, $<expr>, $?<expr>
The first three are unary minus, bitwise complement and logical complement on num-
bers only. The operator, ``$'', 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.
``$?'' tests for the existence of the variable <expr>, and returns 1 if it exists
or 0 otherwise.
Function call. <Expr> must be a string that is the unique prefix of the name of a
builtin window function or the full name of a user defined alias macro. In the
case of a builtin function, <arglist> can be in one of two forms:
<expr1>, <expr2>, . . .
argname1 = <expr1>, argname2 = <expr2>, . . .
The two forms can in fact be intermixed, but the result is unpredictable. Most
arguments can be omitted; default values will be supplied for them. The argnames
can be unique prefixes of the the argument names. The commas separating arguments
are used only to disambiguate, and can usually be omitted.
Only the first argument form is valid for user defined aliases. Aliases are
defined using the alias builtin function (see below). Arguments are accessed via a
variant of the variable mechanism (see ``$'' 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 paren-
thesis surrounding the argument list may be omitted. Aliases return no value.
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 (``<>'').
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 defi-
nition of <string>, if any, is returned. Default for <string-list> is no change.
Close the windows specified in <window-list>. If <window-list> is the word all,
than all windows are closed. No value is returned.
Set the window cursor to modes. Modes is the bitwise or of the mode bits defined
as the variables m_ul (underline), m_rev (reverse video), m_blk (blinking), and
m_grp (graphics, terminal dependent). Return value is the previous modes. Default
is no change. For example, cursor($m_rev|$m_blk) sets the window cursors to blink-
ing reverse video.
Write the list of strings, <string-list>, to window, separated by spaces and termi-
nated 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.
Set the escape character to escape-char. Returns the old escape character as a one
character string. Default is no change. Escapec can be a string of a single char-
acter, or in the form ^X, meaning control-X.
Move window in or out of foreground. 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. Returns the old foreground flag as a number. Default for
window is the current window, default for flag is no change.
Set the label of window to label. Returns the old label as a string. Default for
window is the current window, 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 windows. No value is
Set the default buffer size to nline. Initially, 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.
Make window the current window. The previous current window is returned. Default
is no change.
Set the default window shell program to <string-list>. Returns the first string in
the old shell setting. Default is no change. Initially, the default shell is
taken from the environment variable SHELL.
Read and execute the long commands in filename. Returns -1 if the file cannot be
read, 0 otherwise.
Set terse mode to flag. In terse mode, the command 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.
Undefine alias. Returns -1 if alias does not exist, 0 otherwise.
Undefine variable. Returns -1 if variable does not exist, 0 otherwise.
No arguments. List all variables. No value is returned.
window([row], [column], [nrow], [ncol], [nline], [frame],
[pty], [mapnl], [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. 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). 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 shell, see below). The created window's iden-
tifier is returned as a number.
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.
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, blinking, 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 set-
ting 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 termi-
nal's TERMCAP entry, is used.
~/.windowrc startup command file.
Should be self explanatory.
4.3 Berkeley Distribution May 12, 1986 WINDOW(1)