TED Text Editor
Jump to:
Introduction
Command mode
Screen mode
Introduction
TED is a screen-oriented text
editor that can be used to create new files and edit existing ones. It is a
clone of an editor of the same name that ran under RT-11, although not an
identical one. In particular, this version implements smart tab handling
like the old Borland editors did, and has a different set of screen
editing commands which is more WordStar-like.
The editor does not operate directly on the original text file. Instead,
it loads the text file entirely into its virtual memory buffer, where the
modifications are actually made. When TED is first started, the buffer is
empty. A Read command loads the contents of the file to be edited
into the internal buffer, making it available for edit. Another command,
Write, saves the buffer back into a file.
The three main operations (read, edit and write) are independent of each
other and can be executed in any arbitrary order. To create a new file,
just enter the screen editor and start typing. After saving the text into a
file, we can edit it again and save a different version under a different
file name. With a buffer CLear command we can start again from the
beginning.
The editor has two main modes of operation: command and screen. Command
mode is used mainly for those operations that require one or more parameters
to be specified (e.g. deleting or moving a number of lines, reading a file
either fully of partially, etc.) In screen mode, the user can modify the
text directly by moving the cursor around using the arrow keys of the
keyboard, and by typing or deleting characters and lines.
The maximum line length allowed by the editor is 162 characters. The
maximum file size is limited to about 1 Megabyte, and does not depend on the
amount of RAM available.
Command mode
In the description of commands below we use the following terms and
conventions:
- Square brackets enclose optional parameters.
- FILE means a file specification by the operating system
standards.
- N, N1, N2 are decimal numeric values, often
representing line numbers. The special dollar-sign character "$" can be
used to address the last line in the text buffer or file, depending on
the context.
- P, P1, P2 are text indexes, and represent a
specific position in the text buffer. Text indexes specify both the line
number and the character position within the line. The first character
in a line has always an index value of zero. The index specification can
be:
- A decimal line number, the character "$" (representing the number of the
last line of text) and/or an expression using the arithmetic "+" and "-"
operators. If the resulting value of the expression is greater than the
number of lines currently in the buffer, then the number of the last line is
used. This type of text index specification always sets the character
position to the start of the line.
- A search string, consisting of at least one character. The editor will
try to find the string in the text buffer and, if found, the index
will be set to the first character of the matched string in the text.
The search string must be delimited with one of the following
characters:
! " % & ' = : \ / ? < >
The search string in the description that follow will be represented as:
/STRING/
where in place of "/" any of the characters listed above can be used,
and STRING is any non-empty sequence of characters that does not
contain the delimiter. When such an index is specified, the search
begins from the current cursor position and continues until the end of
the text buffer is reached. If desired, a different start line number
can be specified like this:
/STRING/(N)
in this case, search starts from the N-th line (see above for the
N specification). Search limits can also be specified as:
/STRING/(N1,N2)
The following specifications are also allowed:
/STRING/(,N2)
/STRING/(N1,N2)+N
Command descriptions
TED commands are one or two characters long, optionally followed by one or
more arguments separated by spaces, tabs or a comma.
Commands are ended with either Return or Ctrl-C. When Ctrl-C is used,
the screen editor is entered after command execution.
An empty command is also allowed (e.g. by pressing Return or Ctrl-C at the
prompt). That simply causes the editor to enter the screen mode.
The commands are described below:
Ctrl-Z or EX
Exit editor and return to the operating system. The current text buffer
contents are not automatically saved, so any changes made will be lost.
CL
Clear the text buffer. Any modifications or new text added will be lost
unless saved to a file first.
R [(P)] FILE (N1,N2)
Read the file FILE into the text buffer:
- If N1 and N2 are specified, only the segment from line
N1 to N2 is read, otherwise the whole file is loaded.
- If P is specified, then the file is inserted following the line
P in the current buffer, otherwise the file is appended to the
end.
- The FILE parameter cannot be omitted.
- All trailing spaces in the line are removed.
W [P1 P2] [FILE] [N]
Write the contents of the text buffer from line P1 to P2
into file FILE after line N:
- If P1 and P2 are omitted, the whole contents of the text
buffer is written to the file. If only one parameter is specified, then only
the specified line is written.
- If FILE is omitted, the file name from the latest R command will
be used.
- N can be either zero, or the dollar sign "$". In the first case
the output file is truncated, erasing any old file contents. In the second
case, the file will be opened in append mode and the contents of the text
buffer will be added following the last text line of the file. If the
parameter is not specified, zero is assumed.
F
Display the name of the file read by the last R command. This is the
name that will be used by the W command if the FILE parameter
is omitted.
PR P1 [P2]
Output (PRint) text lines from P1 to P2 to the terminal.
If P2 is omitted, only one line will be displayed. P2 can
also be the dollar sign, which represents the last line of the text. Any
control characters are output as ^X.
D P1 [P2]
Delete lines from P1 to P2 inclusive. If P2 is not
specified, then only a single line is deleted.
M P1 P2 P3
Copy lines from P1 to P2 after line P3.
If P2 equals P1, only a single line is copied.
MD P1 P2 P3
Move lines from P1 to P2 after line P3. The
original lines in the range P1 to P2 are then deleted.
If P2 equals P1 then only a single line is moved.
SU /OLD/NEW/[(N1[,N2])]
SU M /OLD/NEW/[(N1[,N2])]
SU N /OLD/NEW/[(N1[,N2])]
Search and replace text (SUbstitute). OLD is the string to search
for, while NEW is the text that will replace OLD. NEW
can be an empty string, but OLD cannot. Valid delimiter characters
are listed in section 2 above.
The substitute command can work in one of the three following modes:
- The substitution is made everywhere in the text where OLD is found.
This is the default behavior.
- When M is specified as the first parameter, lines containing
OLD are displayed on the terminal with the OLD portion
highlighted by double-quotes, followed by a "Y-<CR>-^C"
prompt:
- To replace text and continue, press "Y".
- To skip the current matched string and continue, press Enter.
- To abort the current and all following substitutions, press Ctrl-C.
- If the number of substitutions to make is known beforehand, then the value
N can be specified in place of the first parameter. In this case the
editor will not ask for confirmation.
In each case the editor displays on the terminal the line after the
substitutions are made.
If necessary, a range of lines where substitutions should be made can be
specified right after NEW, enclosed in parenthesis.
S [P]
Enter screen mode. The top line of the screen will be set to parameter
P, if specified, or to the current text marker.
P [P]
Set text marker to line P. If P is not specified, the
current marker position is displayed.
FR
Displays the amount of available memory.
Command line edition
The command mode allows simple editing of command lines. The editor always
remembers the last command entered, which can be later recalled fully or
partially:
Ctrl-U or Ctrl-^
Delete the current line.
DEL, Backspace or Ctrl-H
Delete one character left.
Left Arrow (Ctrl-S)
Delete one character left.
Right Arrow (Ctrl-D)
Restore one character from the previous command at the current cursor
position.
Up Arrow (Ctrl-E)
Restore all remaining characters from the previous command starting
from the current cursor position.
Ctrl-G
Same as the above, but the command is entered and executed immediately.
Used mostly to repeat the last command entered by typing Ctrl-D at
the editor prompt.
Screen mode
This is the main mode of text edition. The cursor can be moved around the
screen, text entered and/or deleted, etc.
Printable characters are entered at the current cursor position, moving
the cursor one column to the right afterwards. Other operations are performed
via Ctrl-key combinations or dedicated terminal keys:
Left Arrow (Ctrl-S)
Moves the cursor one column left.
Right Arrow (Ctrl-D)
Moves the cursor one column right.
Up Arrow (Ctrl-E)
Moves the cursor one row up. If the cursor is at the top of the screen,
the text is scrolled down.
Down Arrow (Ctrl-X)
Moves the cursor one row down. If the cursor is at the bottom of the
screen, the text is scrolled up.
Home (Ctrl-L)
Moves the cursor to start of the line, or to the end if the cursor was
already on the start column.
Ctrl-T
Moves the cursor to the top line of the screen, or to the bottom one if
the cursor already was on the top line.
Ctrl-F
Moves the cursor to the next tab stop.
Ctrl-Q
Moves the cursor to the previous tab stop.
Tab (Ctrl-I)
Inserts a tab character.
Return or Enter (Ctrl-M)
Splits the line at the current cursor location and moves the cursor to
the start of the next line.
Ctrl-R or Ctrl-_
Redraws the screen.
Ctrl-Y or Ctrl-^
Delete current line, shifting the lines below it one row up.
LF (Ctrl-J)
Inserts an empty line below the current one. The cursor is moved down
to the new line, same column.
Ctrl-K
Inserts an empty line at the current cursor position, shifting the
existing text one row down. The cursor remains on the same location.
DEL or Backspace (Ctrl-H)
Delete character left, shifting the rest of the line one column left.
Ctrl-] or Ctrl-G
Delete character right, shifting the rest of the line one column left.
Ctrl-P
Duplicates the current line. The new line is placed below the current
one, shifting any existing text one row down.
Ctrl-V
Toggle insert/overwrite mode. Default editing mode is overwrite, where
typed characters overwrite the existing text. In insert mode, the text
on the line is shifted one column to the right starting from the cursor
position before the typed character is stored.
Ctrl-B or Ctrl-N
Enter browse mode. The cursor jumps to the bottom of the screen,
below the ruler and the number to the right shows the line number the cursor
was on. In browse mode, the cursor movemente keys work as described below:
Left Arrow (Ctrl-S)
Shift screen window 10 columns left (the text appears to move 10
columns right).
Right Arrow (Ctrl-D)
Shift screen window 10 columns right (the text appears to move
10 columns left).
Up Arrow (Ctrl-E)
Shift screen window 21 lines up (the text appears to scroll 21
lines down, so the top line becomes the bottom one).
Down Arrow (Ctrl-X)
Shift screen window 21 lines down (the text appears to scroll 21
lines up, so the bottom line becomes the top one).
Ctrl-C or Return exits browse mode.
Last modified: 1-May-2019.
|
Contact