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[/] [eco32/] [trunk/] [sim/] [getline/] [getline.3] - Blame information for rev 130

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1 8 hellwig
.\" Note that in silly ol' [nt]roff, even trailing white space is
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.\" significant.  I went through and eliminated it.
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.\" I adopted a convention of using a bold 'getline' when referring to
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.\" the whole package, but an italic 'getline' when referring to the
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.\" specific function.
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.\" Note that in [nt]roff that "-" is a hyphen, while "\-" is a dash.
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.\" I adjusted some source text lines to keep them short (I keep line
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.\" numbers turned on in vi, so I only have 72 cols w/o wrapping).
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.\" It's too bad that getline() doesn't realloc() the buffer as
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.\" necessary.  Then it could have an unlimited input line length.
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.\" Note that .RI et al are limited in how many args they can take.
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.\" I corrected gl_addhist to gl_histadd, which is what is actually
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.\" used!  Perhaps it really should be gl_addhist, to preserve the
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.\" gl_ pattern in the other function names.
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.\" I tried to rephrase certain sections to avoid the passive voice.
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.\" I find the active voice much easier to understand, since I can tell
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.\" more easily what acts on what.
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.TH GETLINE 3
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.SH NAME
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getline \- command-line editing library with history
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.SH SYNOPSIS
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.RI "char *gl_getline(char *" prompt );
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.PP
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.RI "void gl_histadd(char *" line );
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.br
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.RI "void gl_setwidth(int " width );
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.br
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.RI "void gl_strwidth(int " (*width_func)() );
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.PP
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.RI "extern int (*gl_in_hook)(char *" buf );
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.br
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.RI "extern int (*gl_out_hook)(char *" buf );
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.br
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.RI "extern int (*gl_tab_hook)(char *" buf ,
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.RI "int " prompt_width ", int *" cursor_loc );
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.SH DESCRIPTION
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The
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.B getline
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package is a set of library routines that implement
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an editable command-line history.
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.PP
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.B "Programming Interface"
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.br
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.I getline
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returns a pointer to a line of text read from the user,
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prompting the user with the specified
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.IR prompt .
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The pointer refers to a static buffer allocated by the
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.B getline
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package.
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Clients may assume that the pointer
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.I getline
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returns is always the same, and is never NULL.
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The buffer
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.I getline
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returns to the caller contains the terminating newline character,
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except on end of file,
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in which case the first character in the buffer is 0
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.RB ( NUL ).
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File descriptors 0 and 1 must be connected to the terminal
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(not redirected),
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so the caller should check for this condition (using
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.IR isatty (\|))
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and call stdio routines if the session is not interactive.
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.PP
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.I gl_histadd
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adds the given
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.I line
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to the
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.B getline
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history list if the
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.I line
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is not empty and if it is different from the last line
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in the history list
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(so the caller need not check for these conditions).
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.I gl_histadd
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makes its own copies of all the lines it adds to the history list.
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This is so the caller can reuse the buffer it supplies to
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.IR gl_histadd .
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.PP
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.I gl_setwidth
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specifies the terminal
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.I width
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to use for horizontal scrolling.
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The default value is 80 columns,
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and it is important to properly specify the
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.I width
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or lines may wrap inadvertently.
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.PP
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.I gl_strwidth
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allows the application program to supply a prompt string width calculation
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function that returns the number of screen positions used by the argument
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string.
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By default strlen is used, but if the prompt contains escape sequences the user
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can bind a function that returns the actual number of screen postitions
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used by the argument string, not including the escape characters.
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.PP
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In addition to the function call interface,
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.B getline
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has three externally accessible function pointers
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that act as hooks if bound to user-defined functions.
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.B getline
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supplies each of the functions with a pointer to the current buffer
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as the first argument,
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and expects the return value to be the index
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of the first change the function made in the buffer
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(or \-1 if the function did not alter the buffer).
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After the functions return,
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.B getline
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updates the screen as necessary.
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.\"-------
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.\" DWS comment --
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.\"-------
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Note that the functions may not alter the size of the buffer.
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Indeed, they do not even know how large the buffer is!
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.PP
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.I getline
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calls
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.I gl_in_hook
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(initially NULL)
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each time it loads a new buffer.
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More precisely, this is
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.TP
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\(bu
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at the first call to
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.I getline
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(with an empty buffer)
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.TP
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\(bu
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each time the user enters a new buffer from the history list (with
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.B ^P
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or
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.BR ^N )
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.TP
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\(bu
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when the user accepts an incremental search string
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(when the user terminates the search).
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.PP
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.I getline
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calls
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.I gl_out_hook
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(initially NULL)
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when a line has been completed by the user entering a
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.B NEWLINE
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.RB (\| ^J \|)
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or
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.B RETURN
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.RB (\| ^M \|).
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The buffer
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.I gl_out_hook
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sees does not yet have the newline appended, and
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.I gl_out_hook
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should not add a newline.
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.PP
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.I getline
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calls
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.I gl_tab_hook
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whenever the user types a
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.BR TAB .
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In addition to the buffer,
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.I getline
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supplies the current
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.I prompt_width
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(presumably needed for tabbing calculations) and
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.IR cursor_loc ,
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a pointer to the cursor location.
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.RI ( *cursor_loc
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\(eq 0 corresponds to the first character in the buffer)
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.I *cursor_loc
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tells
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.I gl_tab_hook
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where the
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.B TAB
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was typed.
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Note that when it redraws the screen,
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.I getline
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will honor any change
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.I gl_tab_hook
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may make to
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.IR *cursor_loc .
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.\"-------
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.\" DWS comment --
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.\"-------
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Note also that
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.I prompt_width
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may not correspond to the actual width of
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.I prompt
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on the screen if
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.I prompt
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contains escape sequences.
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.I gl_tab_hook
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is initially bound to the
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.B getline
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internal static function
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.IR gl_tab ,
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which acts like a normal
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.B TAB
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key by inserting spaces.
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.PP
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.B "User Interface"
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.br
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.\"-------
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.\" I adapted the prologue to this section from the ksh man page (dws).
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.\"-------
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To edit, the user moves the cursor to the point needing correction and
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then inserts or deletes characters or words as needed.
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All the editing commands are control characters,
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which typed by holding the
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CTRL key down while typing another character.
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Control characters are indicated below as the caret
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.RB (\| ^ \|)
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followed by another character,
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such as
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.BR ^A .
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.PP
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All edit commands operate from any place on the line,
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not just at the beginning.
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.PP
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These are the
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.I getline
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key bindings.
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.\"-------
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.\" Tt  - max width of tag
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.\" Tw  - max width of tag + spacing to the paragraph
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.\" Tp  - special .TP, with the best indent for the editing command
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.\"     descriptions.
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.\"     The first version of Tp prints the tags left-justified.
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.\"     The second version of Tp prints the tags as follows:
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.\"     If one argument is given, it is printed right-justified.
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.\"     If two arguments are given, the first is printed left-justified
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.\"     and the second is printed right-justified.
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.\"-------
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.nr Tt \w'BACKSPACE'
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.nr Tw \w'BACKSPACE\0\0\0'
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.\" .de Tp
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.\" .TP \n(Twu
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.\" \fB\\$1\fR
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.\" ..
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.de Tp
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.TP \n(Twu
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.if \\n(.$=1 \h@\n(Ttu-\w'\fB\\$1\fR'u@\fB\\$1\fR
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.if \\n(.$=2 \fB\\$1\fR\h@\n(Ttu-\w'\fB\\$1\\$2\fR'u@\fB\\$2\fR
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..
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.PP
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.\"-------
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.\" Set interparagraph spacing to zero so binding descriptions are
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.\" kept together.
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.\"-------
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.PD 0
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.Tp "^A"
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Move cursor to beginning of line.
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.Tp "^B"
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Move cursor left (back) 1 column.
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.Tp ESC-B
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Move cursor back one word.
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.Tp "^D"
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Delete the character under the cursor.
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.Tp "^E"
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Move cursor to end of line.
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.Tp "^F"
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Move cursor right (forward) 1 column.
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.Tp ESC-F
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Move cursor forward one word.
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.Tp "^H"
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Delete the character left of the cursor.@
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.Tp "^I"
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Jump to next tab stop (may be redefined by the program).
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.Tp "^J"
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Return the current line.
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.Tp "^K"
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Kill from cursor to the end of the line (see
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.BR "^Y" \|).
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.Tp "^L"
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Redisplay current line.
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.Tp "^M"
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Return the current line.
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.Tp "^N"
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Fetches next line from the history list.
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.Tp "^O"
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Toggle overwrite/insert mode, initially in insert mode.
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.Tp "^P"
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Fetches previous line from the history list.
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.Tp "^R"
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Begin a reverse incremental search through history list.
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Each printing character typed adds to the search substring
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(initially empty), and
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.B getline
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finds and displays the first matching location.
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Typing
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.B ^R
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again marks the current starting location and begins a new
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search for the current substring.
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Typing
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.B ^H
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or
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.B DEL
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deletes the last character from the search string,
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and
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.B getline
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restarts the search from the last starting location.
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Repeated
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.B ^H
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or
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.B DEL
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characters therefore appear to unwind the search to the match nearest
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the point where the user last typed
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.B ^R
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or
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.BR ^S .
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Typing
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.B ^H
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or
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.B DEL
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until the search string is empty causes
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.B getline
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to reset the start of the search to the beginning of the history list.
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Typing
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.B ESC
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or any other editing character accepts the current match
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and terminates the search.
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.Tp "^S"
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Begin a forward incremental search through the history list.
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The behavior is like that of
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.B ^R
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but in the opposite direction through the history list.
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.Tp "^T"
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Transpose current and previous character.
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.Tp "^U"
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Kill the entire line (see
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.BR "^Y" \|).
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.Tp "^Y"
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Yank previously killed text back at current location.
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.Tp BACKSPACE
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Delete the character left of the cursor.
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.Tp DEL
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Delete the character left of the cursor.
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.Tp RETURN
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Return the current line.
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.Tp TAB
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Jump to next tab stop (may be redefined by the program).
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.\"-------
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.\" Restore default interparagraph spacing.
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.\"-------
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.PD
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.PP
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.B getline
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recognizes DOS and ANSI arrow keys.
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They cause the following actions:
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.B up
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is the same as
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.BR ^P ,
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.B down
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is the same as
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.BR ^N ,
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.B left
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is the same as
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.BR ^P ,
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and
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.B right
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is the same as
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.BR ^F .
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.SH AUTHORS
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.PP
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Program by
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Christopher R. Thewalt (thewalt\|@ce.berkeley.edu)
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.PP
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Original man page by
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DaviD W. Sanderson (dws\|@cs.wisc.edu)
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and Christopher R. Thewalt
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.SH COPYRIGHT
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\&
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.br
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.if n (C)
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.if t \s+8\v'+2p'\fB\(co\fR\v'-2p'\s0
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\s+2Copyright 1992,1993 by Christopher R. Thewalt and DaviD W. Sanderson\s0
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(but freely redistributable)

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