edit - Edits a file line by line with a simplified command
set
edit [-c subcommand] [-lRv] [-wnumber] [+subcommand] [-]
[file...]
edit [-c subcommand] [-lRv] [-t tag] [file...]
edit [-c subcommand] -r[file] [-lRv] [file]
The edit command provides a line editor designed for
beginning users.
Indents appropriately for LISP code, and accepts the (, ),
{, }, [, and ] characters (parentheses, braces, and brackets)
as text rather than interpreting them as vi subcommands.
The LISP modifier is active in open or visual
modes. Recovers file after an editor or system crash. If
you do not specify file, a list of all saved files is displayed.
Sets the readonly option, preventing you from
altering the file. Loads the file that contains tag and
positions the editor at tag. To use this option, you must
first create a database of function names and locations
using the ctags command. Invokes the visual editor. When
the -v option is specified, an enlarged set of subcommands
are available, including screen editing and cursor movement
features. See vi. Sets the default window size to
number lines. Suppresses all interactive user feedback.
If you use this option, file input/output errors do not
generate an error message. Begins the edit with the specified
editor search or subcommand. When subcommand is not
entered, a + (plus sign) sets the current line to the bottom
of the file. Normally edit sets the current line to
the last line of the file, or to some specified tag or
pattern.
The edit command is part of a family of editors that also
includes ed, ex, and vi. It is a simplified version of the
ex editor, which itself is built on the ed line editor.
To edit the contents of a file, enter: edit file
If file is the name of an existing file, edit copies it to
a buffer and displays the number of lines and characters
in it. Then it displays a : (colon) prompt to show that
it is ready to read subcommands from standard input.
If file does not already exist, edit tells you this. You
can give more than one file, in which case edit copies the
first file into its buffer and stores the remaining filenames
in an argument list for later use.
The edit command does not make changes to the file until
you use the w subcommand to write the changes.
Editing Modes [Toc] [Back]
The edit command operates in one of two modes: In command
mode, the edit editor recognizes and executes subcommands.
When you start the editor, it is in command mode. In text
input mode, you can add text to the editing buffer. You
enter text input mode by using the a, c, or i subcommand.
To exit text input mode (and return to command mode), you
enter a (dot) alone at the beginning of a line.
Subcommand Syntax [Toc] [Back]
The general format of an edit subcommand is as follows:
[address]subcommand[argument ...][count]
If you do not specify an address, edit works on the current
line. When you start the edit program, the current
line is the last line in the buffer. As you edit the
buffer, the current line changes to the last line affected
by a subcommand. (When edit reads a file into its buffer,
the last line affected by the process of reading is the
last line in the file.) If you add a numeric count to most
subcommands, edit works on the specified number of lines.
The value for address can be a line number or a pattern to
be matched or, in some cases, a range of line numbers or
patterns. To specify a range, separate two line numbers
or patterns with a comma or a semicolon (for example, 1,5
or 1;5). In a range, the second address must refer to a
line that follows the first addressed line in the range.
To work with different parts of a file, you must know how
to find out the current line and how to address different
lines in a file.
Addressing Lines Within a File [Toc] [Back]
The simplest way to address a line within a file is to use
its line number. But this can be unreliable because line
numbers change when you insert and delete lines. The edit
command provides a way to search through the buffer for
strings. Given the following address, edit searches forward
for pattern: /pattern/
If given the following address, edit searches backward for
pattern: ?pattern?
If a forward search reaches the end of the buffer without
finding pattern, it continues the search at the beginning
of the file until it reaches the current line. A backward
search does just the reverse.
The following characters have special meanings in these
search patterns: Matches the beginning of a line. Matches
the end of a line.
Thus, you can use /^pattern/ to search for patterns at the
beginning of a line, and /pattern$/ to search for patterns
at the end of the line. Lines can be addressed by their
line numbers; for example, 11 refers to line 11 of the
buffer. In addition, the current line is addressed with a
(dot) and the last line in the buffer is addressed with a
$ (dollar sign). This is useful when working with a range
of lines. For example, the following command displays all
lines from the current line to the last line in the
buffer: .,$print
Do not confuse the meaning of $ in text patterns, end of
line, with its meaning in addresses, last line. Arithmetic
with line references is also possible, so that $-5 refers
to the fifth line from the last and refers to the line 20
lines past the current line. You can also use the =
(equal sign) command to find out the line number of the
current line or the last line, as follows: .= $=
To view the next line in the buffer, press <Return>.
Press <Ctrl-d> to display the next half-screen of lines.
Using a Family of Editors [Toc] [Back]
As you become more experienced with edit, you might want
to try the advanced features of one of the other editors
in the family. Because edit is part of a family of editors,
you can apply your knowledge of edit to the other
editors in the family.
The ex editor is a powerful interactive line editor. The
edit subcommands work the same way in ex, but the editing
environment is somewhat different. For example in edit,
only the characters ^ (circumflex), $ (dollar sign), and \
(backslash) have special meanings as pattern-matching
characters; however, several additional characters also
have special meanings in ex.
Unless otherwise noted, all subcommands work by default on
the current line; address is optional. You can use the
full subcommand or its abbreviation. Subcommand abbreviations
appear after the command in the sections that follow.
You can use the 1,$p subcommand to display the entire contents
of the buffer.
The edit program recognizes and interprets the following
subcommands when it displays the colon prompt.
Adding Text [Toc] [Back]
Appends the text you type after the current line, if you
do not specify an address. If you specify an address, the
a subcommand appends text after the addressed line. If
you specify address 0 (zero), the a subcommand places the
text at the beginning of the buffer. As you type your
text, press <Return> at the end of each line. When you
have entered all your text, enter a (dot) alone at the
start of a line. This ends text input mode and returns to
command mode. Places the given text before the specified
line. Enter a (dot) to return to command mode. The last
line input becomes the current line.
Changing Text [Toc] [Back]
Replaces the current line or addressed line or lines with
the input text. Enter a (dot) to return to command mode.
If any lines are input, the last input line becomes the
new current line.
Deleting Text [Toc] [Back]
Removes the specified line or lines from the editing
buffer. The line following the last deleted line becomes
the current line. If you specify a buffer by giving a letter
from a to z, edit saves the specified lines in that
buffer or, if the letter is uppercase, appends the lines
to that buffer.
Displaying Text and Determining the Current Line [Toc] [Back]
Displays the current filename along with the following
information: Whether it was modified since the last write.
What the current line is. How many lines are in the
buffer. What percentage of the way through the buffer the
current line is.
Also, sets the current filename if file is specified.
Displays each specified line or lines preceded
by its buffer line number. The last line
displayed becomes the current line. Displays the
specified line or lines. The last line displayed
becomes the current line. Displays the line number
of the addressed line. If you do not specify an
address, displays the line number of the last line.
Displays a screen of text, beginning with the current
or specified line. Displays a screen of text,
with the specified (or current) line at the bottom
of the screen. Displays a screen of text, with the
specified (or current) line in the middle of the
screen.
Editing Another File [Toc] [Back]
Begins an editing session on a new file. The editor first
checks to see if the buffer was modified since the last
write subcommand. If it has, edit issues a warning and
cancels the edit subcommand. Otherwise, it deletes the
complete contents of the editor buffer, makes the named
file the current file, and displays the new filename.
After ensuring that this file can be edited, it reads the
file into its buffer. If edit reads the file without
error, it displays the number of lines and characters that
it read. The last line read becomes the new current line.
Copies the next file in the command line argument list to
the buffer for editing.
You can edit a sequence or group of files. You can
use the next subcommand to edit each file on the
command line in turn, or to specify a list of filenames
to edit (using the shell pattern matching
syntax) instead. The wildcard character % represents
the name of the current edit file and can be
used to form filenames. If file is specified, the
command line argument list is replaced, and an edit
command is performed on the first file.
Making Global Changes [Toc] [Back]
Marks each of the specified lines that matches the pattern,
then carries out the specified subcommands (commands)
on each marked line.
A single command or the first command in a subcommand
list appears on the same line as global. The
remaining commands must appear on separate lines,
where each line (except the last) ends with a \
(backslash). The default subcommand is print.
The subcommand list can include the append, insert,
and change subcommands and their associated input.
In this case, if the ending period comes on the
last line of the command list, you can omit it.
The undo subcommand and the global subcommand
itself, however, cannot appear in the command list.
See also Substituting Text.
Moving or Copying Text [Toc] [Back]
Repositions the specified line or lines to follow
address3. The first of the moved lines becomes the current
line. address1 and address2 are optional; you must specify
address3. Places the specified line or lines in
buffer (identified by a single alpha character name a to
z). Retrieves the contents of the specified buffer and
places it after address. If you do not specify a buffer,
edit restores the last deleted or yanked text. Thus, you
can use this subcommand together with delete to move lines
or with yank to duplicate lines between files.
Quitting an Editing Session [Toc] [Back]
Ends the editing session. The quit command does not write
the editor buffer to a file; if you have modified the contents
of the buffer since the last write, edit displays a
warning message and does not end the session. In this
case, either use the quit! subcommand to discard the
buffer or write the buffer and then quit.
Saving Text [Toc] [Back]
Writes the contents of the specified line or lines to
file. The default range is all lines in the buffer. edit
displays the number of lines and characters that it
writes. If you do not specify a file, edit uses the current
filename. If file does not exist, edit creates it.
Saves the current editor buffer as though the system had
just crashed. Use this command when a write subcommand
has resulted in an error, and you do not know how to save
your work. Recovers file from the system save area. Use
this after a system crash, or a preserve subcommand.
Substituting Text [Toc] [Back]
Replaces on each specified line the first instance of pattern
with the replacement pattern replacement. If you add
the global indicator g, it replaces all instances of pattern
on each specified line.
Undoing a Change [Toc] [Back]
Reverses the changes made in the buffer by the last buffer
editing subcommand. Note that global subcommands are considered
a single subcommand to an undo. You cannot undo a
write or an edit subcommand.
Commands: ed(1), ex(1), vi(1)
edit(1)
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