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WINDOW(1) DragonFly General Commands Manual WINDOW(1)
NAME
window - window environment
SYNOPSIS
window [-dft] [-c command] [-e escape-char]
DESCRIPTION
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 communicate 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 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 below) contained
in the file .windowrc 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:
-c command Execute the string command as a long command (see below)
before doing anything else.
-d Ignore .windowrc and create the two default windows 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.
-f Fast. Don't perform any startup action.
-t Turn on terse mode (see terse command below).
Windows can overlap and are framed as necessary. Each window is named by
one of the digits "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 designated 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 (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 addition,
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 input, output,
and diagnostic file descriptors are bound to one end of either a pseudo-
terminal (see pty(4)) or a UNIX domain socket (see socketpair(2)). 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 (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-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
information 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 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 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" 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 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 window. The cursor
is placed on the screen and the keys "h", "j", "k", and "l" move
the cursor left, down, up, and right, respectively. 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)). 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 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
current 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. Normal line
editing 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. Alternatively, non-alphanumeric characters can be included in
strings by quoting them in double (""") quotes or escaping them with
backslash ("\"). 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 preceded 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 terminated with a new line or ";". To continue an
expression on the next line, terminate the first line with "\".
Conditional Statement
window 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 language, 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 discarded 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> evaluates true (non-
zero 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. 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>,
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>, $?<expr>
The first three are unary minus, bitwise complement and
logical complement on numbers only. The operator, "$", 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. "$?" tests for the existence of the
variable <expr>, and returns 1 if it exists or 0 otherwise.
<expr>(<arglist>)
Function call. <Expr> must be a string that is the unique
prefix of the name of a builtin window function or the full
name of a user defined alias macro. In the case of a builtin
function, <arglist> can be in one of two forms:
<expr1>, <expr2>, ...
argname1 = <expr1>, argname2 = <expr2>, ...
The two forms can in fact be intermixed, but the result is
unpredictable. Most arguments can be omitted; default values
will be supplied for them. The argnames can be unique
prefixes of the argument names. The commas separating
arguments are used only to disambiguate, and can usually be
omitted.
Only the first argument form is valid for user defined
aliases. Aliases are defined using the alias builtin
function (see below). Arguments are accessed via a variant
of the variable mechanism (see "$" 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 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 definition 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 (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 blinking reverse video.
default_nline([nline])
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.
default_shell([<string-list>])
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.
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. Returns the old
escape character as a one-character string. Default 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 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 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 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.
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
default 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, 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 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
window uses these environment variables: HOME, SHELL, TERM, TERMCAP,
WINDOW_ID.
FILES
~/.windowrc startup command file.
/dev/[pt]ty[pq]? pseudo-terminal devices.
EXAMPLES
The following example ~/.windowrc will open two windows. The upper one
will take one third of the screen and run tcpdump, the lower one will
take the remaining two thirds of the screen and run the default shell:
window r=1, nr=$nrow/3-1, l=tcpdump\ pcn0, sh=tcpdump \-ni pcn0
window r=$nrow/3, nr=2*$nrow/3+1
DIAGNOSTICS
Should be self explanatory.
HISTORY
The window command appeared in 4.3BSD.
DragonFly 6.5-DEVELOPMENT February 21, 2023 DragonFly 6.5-DEVELOPMENT