This line is composed of three parts. On the left, Last=0
indicates that the
last line of your text is line 0. You therefore have an empty buffer (zero
lines). Next to this, the numbers in brackets (0,1) indicate
the current
position of the cursor in the file. It is of the form
(row,column).
The row indicates your current line and for all but an empty buffer it
will range
in value between 1 and Last. On attached terminals you may find that the
column number does not change.
Next on the line are your current editing options. A + (plus)
after an option indicates that the option is on while a
- (minus) indicates that it is off. Some options
which are meant to catch your attention when on will display a
flashing +. These options may be turned on and
off at the command line. Some of the options are also tied in with function
keys. They are toggled on/off by the indicated key.
Briefly the options have the following meaning:
- a - Anchor (Alt–a)
- This option will be better understood after reading the
section on pattern matching. For now it is enough to know that the editor has
the ability to search for text strings and leave your cursor at the string
matched. Should you specify a search for the string "mouse" with this option
on (a+), your
cursor will be anchored to the start of the pattern matched
(in this case "m").
With (a-), the cursor would be positioned at the character
after the matched
string "mouse" (in this case the character after the
"e").
- b - Blank (Alt–b)
- When viewing a piece of text on the screen,
lines appear to be padded with blanks to the end of the screen. Since the
editor reads files with variable sized lines containing 0 (a line containing only
a carriage return) to 256 characters, you may wonder whether the blanks at the
end of the line are real or not. With b+, the editor will allow you to
differentiate between real blanks by displaying nulls (non-existent characters)
as small centered dots.
- c - Command (keypad +)
- This option indicates whether your active cursor is in
the command area (c+) or text area (c-).
- d - Dual (Alt–d)
- This option, like option anchor (a), concerns pattern matching.
If off (d-) then a search for "mouse"
would match the string "MOUSE",
"MoUse", "MOUsE" and so on in your
text. If on (d+), the pattern matcher
differentiates between upper and lower case.
- f - Fill (Alt–f)
- This option when on (f+) will cause automatic filling of input
lines at your defined right margin. The default right margin is column 60.
Should you attempt to enter a character in this column then any preceding
characters of a word will be moved to the next line. Using this option you
may enter text without ever having to type a carriage return
to end each line. This is extremely useful when entering documentation and
letters.
- i - Insert (Ins)
- When on (i+), all characters typed will be inserted before the
character at the current cursor position.
- j - Justify (Alt–j)
- This option is used in conjunction with option fill (f+). When both option
fill and option justify (j+) are on then when each line is filled it
will also be justified.
- l - Limit (Alt–l)
- This option will flash (l+) when a tagged operation is being
limited between a left and right limit.
- m - Meta (Alt–m)
- When on (m+), meta characters are enabled during pattern matching. A meta
character is a character which has special significance to the pattern
matcher. For instance the character dot (.) is a meta character that
will match ANY character, not just a dot. This
option will be explained in greater detail later.
- n - Newline (F1 or F2 keys)
- Whenever a carriage return is entered in the text
area while this option is on, a new line will open up after your current line
to allow you to type in new text. This can be thought of as line insert mode
and is similar to character insert mode (i+).
- s - Save (Alt–s)
- When on (s+), your buffer will be automatically saved in the
file autosave after every 20 lines of input. While writing to the disk
you may still continue to type up to 256 characters per line, however, your
keys will not be echoed (shown on the screen) until the write is complete.
- t - Tabs (Alt–t)
- This option is similar to option Blank.
Tab characters in your text are expanded into enough spaces to reach the next tab
stop. What may appear as 4 spaces may only be one "real" character. Turning
this option on (t+) will display the actual tab character as a right triangle.
When option Blank is also on (b+), the spaces which pad the
tab to the next tab stop will be
displayed as centered dots since they do not exist within the buffer. Tabs
are characters which are heavily used within C programs for
indentation.
- w - Wrap (Alt–w)
- This option allows pattern searches to wrap around from bottom to top or
top to bottom when on (w+). If off, then
pattern matching will stop
when it reaches the last or first line of the buffer.