MirOS Manual: window(1)

WINDOW(1)                    BSD Reference 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 associ-
     ated 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 options are as follows:

     -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 the terse command below).

     Windows can overlap and are framed as necessary. Each window is named by
     one of the digits 1-9. 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 por-
     tion 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 avail-
     able if they are supported by the terminal. In addition, similar to ter-
     minals 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 pro-
     cess 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(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 (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 pro-
     duced 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 particu-
     lar, 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 the 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 ter-
     minal screen becomes the command prompt window, and window interprets in-
     put 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 1-9 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 the
             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 sig-
             nal (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 win-
             dow 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 support-
             ed.

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 expres-
     sions 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 newline, '\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 state-
     ments 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 (non-array) 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 if 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 returned (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>, $?<expr>
                 The first three are unary minus, bitwise complement and logi-
                 cal complement on numbers only. The operator '$' 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 built-in window function or the full
                 name of a user defined alias macro. In the case of a built-in
                 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 pre-
                 fixes 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 built-in func-
                 tion (see below). Arguments are accessed via a variant of the
                 variable mechanism (see the '$' operator above).

                 Most functions return value, but some are used for side ef-
                 fect only and so must be used as statements. When a function
                 or an alias is used as a statement, the parentheses surround-
                 ing the argument list may be omitted. Aliases return no
                 value.

Built-in functions

     The arguments are listed by name in their natural order. Optional argu-
     ments 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 mean-
     ings, 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. De-
                 fault 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>. Re-
                 turns the first string in the old shell setting. Default is
                 no change. Initially, the default shell is taken from the en-
                 vironment 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, separat-
                 ed 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 es-
                 cape 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 other-
                 wise.

     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, leftmost, lower, or rightmost
                 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, respec-
                 tively, put a frame around this window (default true), allo-
                 cate 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 (de-
                 fault false) prevents this action. When smooth is true, the
                 screen is updated more frequently (for this window) to pro-
                 duce 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 speci-
                 fied by default_shell, see above). The created window's iden-
                 tifier 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 bit-
            wise 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 utilizes these environment variables: HOME, SHELL, TERM, TERMCAP,
     WINDOW_ID.

FILES

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

HISTORY

     The window command appeared in 4.3BSD.

MirOS BSD #10-current         December 30, 1993                              7

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