window.1

早期freebsd实现

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.\" Edward Wang at The University of California, Berkeley.
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.\"	@(#)window.1	8.2 (Berkeley) 12/30/93
.\"
.Dd December 30, 1993
.Dt WINDOW 1
.Os BSD 4.3
.Sh NAME
.Nm window
.Nd window environment
.Sh SYNOPSIS
.Nm window
.Op Fl t
.Op Fl f
.Op Fl d
.Op Fl e Ar escape-char
.Op Fl c Ar command
.Sh DESCRIPTION
.Nm Window
implements a window environment on
.Tn ASCII
terminals.
.Pp
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.
.Pp
When
.Nm window
starts up, the commands (see long commands below)
contained in the file
.Pa .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.
.Pp
The command line options are
.Bl -tag -width Fl
.It Fl t
Turn on terse mode (see
.Ic terse
command below).
.It Fl f
Fast.  Don't perform any startup action.
.It Fl d
Ignore
.Pa .windowrc
and create the two default
windows instead.
.It Fl e Ar escape-char 
Set the escape character to
.Ar escape-char  .
.Ar Escape-char
can be a single character, or in the form
.Ic ^X
where
.Ar X
is any character, meaning
.No control\- Ns Ar X  . 
.It Fl c Ar command 
Execute the string
.Ar command
as a long command (see below)
before doing anything else.
.El
.Pp
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
.Ar 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.
.Pp
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.
.Ss 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
.Xr (pty 4 )
or a
.Ux
domain socket
.Xr (socketpair 4 ) .
If a pseudo-terminal is used, then its special
characters and modes (see
.Xr stty 1 )
are copied from the physical
terminal.  A
.Xr termcap 5
entry tailored to this window is created
and passed as environment
.Xr (environ 5 )
variable
.Ev 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
.Xr vi 1
uses
this information to redraw its display.
.Ss Operation
During normal execution,
.Nm 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.
.Pp
Typing
.Nm window Ns 's 
escape character (normally
.Ic ^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
.Nm window
interprets input from the keyboard as commands to manipulate windows.
.Pp
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
.Dq Ic \&:
command below), or read from a file (see
.Ic source
below).
.Ss Short Commands
Below,
.Ar \&#
represents one of the digits ``1'' to ``9''
corresponding to the windows 1 to 9.
.Ic ^X
means
.No control\- Ns Ar X  , 
where
.Ar X
is any character.  In particular,
.Ic ^^
is
.Li control\-^.
.Ar Escape
is the escape key, or
.Ic ^\&[ .
.Bl -tag -width Ds
.It Ar #
Select window
.Ar #
as the current window
and return to conversation mode.
.It Ic \&% Ns Ar # 
Select window
.Ar #
but stay in command mode.
.It Ic ^^
Select the previous window and return to conversation
mode.  This is useful for toggling between two windows.
.It Ic escape
Return to conversation mode.
.It Ic ^P
Return to conversation mode and write
.Ic ^P
to the
current window.  Thus, typing two
.Ic ^P Ns 's
in conversation
mode sends one to the current window.  If the
.Nm window
escape is changed to some other character, that
character takes the place of
.Ic ^P
here.
.It Ic ?
List a short summary of commands.
.It Ic ^L
Refresh the screen.
.It Ic q
Exit
.Nm window  .
Confirmation is requested.
.It Ic ^Z
Suspend
.Nm window  .
.It Ic 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.
.Pp
This window becomes the current window,
and is given the first available ID.  The default buffer size
is used (see
.Ar default_nline
command below).
.Pp
Only fully visible windows can be created this way.
.It Ic c Ns Ar # 
Close window
.Ar # .
The process in the window is sent
the hangup signal (see
.Xr kill 1 ) .
.Xr Csh 1
should
handle this signal correctly and cause no problems.
.It Ic m Ns Ar # 
Move window
.Ar #
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
.Ic w
command are used to position the box.  The
window can be moved partially off-screen.
.It Ic M Ns Ar # 
Move window
.Ar #
to its previous position.
.It Ic s Ns Ar # 
Change the size of window
.Ar # .
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
.Ic w
and
.Ic m
are used to enter the position.
.It Ic S Ns Ar # 
Change window
.Ar #
to its previous size.
.It Ic ^Y
Scroll the current window up by one line.
.It Ic ^E
Scroll the current window down by one line.
.It Ic ^U
Scroll the current window up by half the window size.
.It Ic ^D
Scroll the current window down by half the window size.
.It Ic ^B
Scroll the current window up by the full window size.
.It Ic ^F
Scroll the current window down by the full window size.
.It Ic h
Move the cursor of the current window left by one column.
.It Ic j
Move the cursor of the current window down by one line.
.It Ic k
Move the cursor of the current window up by one line.
.It Ic l
Move the cursor of the current window right by one column.
.It Ic 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.
.It Ic p
Put.  The content of the yank buffer is written to the current
window as input.
.It Ic ^S
Stop output in the current window.
.It Ic ^Q
Start output in the current window.
.It Ic :
Enter a line to be executed as long commands.
Normal line
editing characters (erase character, erase word, erase line)
are supported.
.El
.Ss 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.
.Pp
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".
.Pp
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.
.Pp
The character ``#'' begins a comment which terminates at the
end of the line.
.Pp
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 ``\\''.
.Ss Conditional Statement
.Nm Window
has a single control structure:
the fully bracketed if statement in the form
.Pp
.Bd -literal -offset indent -compact
if <expr> then
\t<statement>
\t...
elsif <expr> then
\t<statement>
\t...
else
\t<statement>
\t...
endif
.Ed
.Pp
The
.Ic else
and
.Ic elsif
parts are optional, and the latter can
be repeated any number of times.
<Expr>
must be numeric.
.Ss Expressions
Expressions in
.Nm 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.
.Pp
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.
.Pp
Single valued (no arrays) variables are supported, of both
numeric and string values.  Some variables are predefined.  They
are listed below.
.Pp
The operators in order of increasing precedence:
.Bl -tag -width Fl
.It Xo
.Aq Va expr1
.Ic =
.Aq Va expr2
.Xc
Assignment.  The variable of name
.Aq Va expr1 , 
which must be string valued,
is assigned the result of
.Aq Va expr2 . 
Returns the value of
.Aq Va expr2 . 
.It Xo
.Aq Va expr1
.Ic ?
.Aq Va expr2
.Ic :
.Aq Va expr3
.Xc
Returns the value of
.Aq Va expr2 
if
.Aq Va expr1 
evaluates true
(non-zero numeric value); returns the value of
.Aq Va expr3 
otherwise.  Only
one of
.Aq Va expr2 
and
.Aq Va expr3 
is evaluated.
.Aq Va Expr1 
must
be numeric.
.It Xo
.Aq Va expr1
.Ic \&|\&|
.Aq Va expr2
.Xc
Logical or.  Numeric values only.  Short circuit evaluation is supported
(i.e., if
.Aq Va expr1 
evaluates true, then
.Aq Va expr2 
is not evaluated).
.It Xo
.Aq Va expr1
.Ic \&&\&&
.Aq Va expr2
.Xc
Logical and with short circuit evaluation.  Numeric values only.
.It Xo
.Aq Va expr1
.Ic \&|
.Aq Va expr2
.Xc
Bitwise or.  Numeric values only.
.It Xo
.Aq Va expr1
.Ic ^
.Aq Va expr2
.Xc
Bitwise exclusive or.  Numeric values only.