ED(I) 1/15/73 ED(I)
NAME
ed - editor
SYNOPSIS
ed [ - ] [ name ]
DESCRIPTION
Ed is the standard text editor.
If a name argument is given, ed simulates an e command (see
below) on the named file; that is to say, the file is read
into ed's buffer so that it can be edited. The optional -
simulates an os command (see below) which suppresses the
printing of characters counts by e, r, and w commands.
Ed operates on a copy of any file it is editing; changes
made in the copy have no effect on the file until a w
(write) command is given. The copy of the text being edited
resides in a temporary file called the buffer. There is
only one buffer.
Commands to ed have a simple and regular structure: zero or
more addresses followed by a single character command,
possibly followed by parameters to the command. These
addresses specify one or more lines in the buffer. Every
command which requires addresses has default addresses, so
that the addresses can often be omitted.
In general, only one command may appear on a line. Certain
commands allow the input of text. This text is placed in
the appropriate place in the buffer. While ed is accepting
text, it is said to be in input mode. In this mode, no
commands are recognized; all input is merely collected.
Input mode is left by typing a period `.' alone at the
beginning of a line.
Ed supports a limited form of regular expression notation.
A regular expression is an expression which specifies a set
of strings of characters. A member of this set of strings
is said to be matched by the regular expression. The
regular expressions allowed by ed are constructed as
follows:
1. An ordinary character (not one of those discussed
below) is a regular expression and matches that
character.
2. A circumflex `^' at the beginning of a regular
expression matches the null character at the beginning
of a line.
3. A currency symbol `$' at the end of a regular
expression matches the null character at the end of a
line.
4. A period `.' matches any character but a new-line
character.
5. A regular expression followed by an asterisk `*'
matches any number of adjacent occurrences (including
zero) of the regular expression it follows.
6. A string of characters enclosed in square brackets `[
]' matches any character in the string but no others.
If, however, the first character of the string is a
circumflex `^' the regular expression matches any
character but new-line and the characters in the
string.
7. The concatenation of regular expressions is a regular
expression which matches the concatenation of the
strings matched by the components of the regular
expression.
8. The null regular expression standing alone is
equivalent to the last regular expression encountered.
Regular expressions are used in addresses to specify lines
and in one command (see s below) to specify a portion of a
line which is to be replaced.
If it is desired to use one of the regular expression
metacharacters as an ordinary character, that character may
be preceded by `\'. This also applies to the character
bounding the regular expression (often `/') and to `\'
itself.
Addresses are constructed as follows. To understand
addressing in ed it is necessary to know that at any time
there is a current line. Generally speaking, the current
line is the last line affected by a command; however, the
exact effect on the current line by each command is
discussed under the description of the command.
1. The character `.' addresses the current line.
2. The character `^' addresses the line immediately
before the current line.
3. The character `$' addresses the last line of the
buffer.
4. A decimal number n addresses the n-th line of the
buffer.
5. `'x' addresses the line associated (marked) with the
mark name character x which must be a printable
character. Lines are marked with the k command
described below.
6. A regular expression enclosed in slashes `/'
addresses the first line found by searching toward the
end of the buffer and stopping at the first line
containing a string matching the regular expression.
If necessary the search wraps around to the beginning
of the buffer.
7. A regular expression enclosed in queries `?'
addresses the first line found by searching toward the
beginning of the buffer and stopping at the first line
found containing a string matching the regular
expression. If necessary the search wraps around to
the end of the buffer.
8. An address followed by a plus sign `+' or a minus
sign `-' followed by a decimal number specifies that
address plus (resp. minus) the indicated number of
lines. The plus sign may be omitted.
Commands may require zero, one, or two addresses. Commands
which require no addresses regard the presence of an address
as an error. Commands which accept one or two addresses
assume default addresses when insufficient are given. If
more addresses are given than such a command requires, the
last one or two (depending on what is accepted) are used.
Addresses are separated from each other typically by a comma
`,'. They may also be separated by a semicolon `;'. In
this case the current line `.' is set to the previous
address before the next address is interpreted. This
feature can be used to determine the starting line for
forward and backward searches (`/', `?'). The second
address of any two-address sequence must correspond to a
line following the line corresponding to the first address.
In the following list of ed commands, the default addresses
are shown in parentheses. The parentheses are not part of
the address, but are used to show that the given addresses
are the default.
As mentioned, it is generally illegal for more than one
command to appear on a line. However, any command may be
suffixed by `p' (for `print'). In that case, the current
line is printed after the command is complete.
( . )a
<text>
.
The append command reads the given text and
appends it after the addressed line. `.' is left
on the last line input, if there were any,
otherwise at the addressed line. Address `0' is
legal for this command; text is placed at the
beginning of the buffer.
( . , . )c
<text>
.
The change command deletes the addressed lines,
then accepts input text which replaces these
lines. `.' is left at the last line input; if
there were none, it is left at the first line not
changed.
( . , . ) d
The delete command deletes the addressed lines
from the buffer. The line originally after the
last line deleted becomes the current line; if the
lines deleted were originally at the end, the new
last line becomes the current line.
e filename
The edit command causes the entire contents of the
buffer to be deleted, and then the named file to
be read in. `.' is set to the last line of the
buffer. The number of characters read is typed.
`filename' is remembered for possible use as a
default file name in a subsequent r or w command.
f filename
The filename command prints the currently
remembered file name. If `filename' is given, the
currently remembered file name is changed to
`filename'.
(1,$)g/regular expression/command list
In the global command, the first step is to mark
every line which matches the given regular
expression. Then for every such line, the given
command list is executed with `.' initially set to
that line. A single command or the first of
multiple commands appears on the same line with
the global command. All lines of a multi-line
list except the last line must be ended with `\'.
A, i, and c commands and associated input are
permitted; the `.' terminating input mode may be
omitted if it would be on the last line of the
command list. The (global) commands, g, and v,
are not permitted in the command list.
( . )i
<text>
.
This command inserts the given text before the
addressed line. `.' is left at the last line
input; if there were none, at the addressed line.
This command differs from the a command only in
the placement of the text.
( . )kx
The mark command associates or marks the addressed
line with the single character mark name x. The
ten most recent mark names are remembered. The
current mark names may be printed with the n
command.
( . , . )l
The list command will print the addressed lines in
a way that is unambiguous: Non-graphic characters
are printed in octal, prefixed characters are
overstruck with a circumflex, and long lines are
folded.
( . , . )ma
The move command will reposition the addressed
lines after the line addressed by a. The last of
the moved lines becomes the current line.
n
The n command will print the current mark names.
os
ov
After os character counts printed by e, r, and w
are suppressed. Ov turns them back on.
( . , . )p
The print command prints the addressed lines. `.'
is left at the last line printed. The p command
may be placed on the same line after any command.
q
The quit command causes ed to exit. No automatic
write of a file is done.
($)r filename
The read command reads in the given file after the
addressed line. If no file name is given, the
remembered file name, if any, is used (see e and f
commands). The remembered file name is not
changed unless `filename' is the very first file
name mentioned. Address `0' is legal for r and
causes the file to be read at the beginning of the
buffer. If the read is successful, the number of
characters read is typed. `.' is left at the last
line read in from the file.
( . , . )s/regular expression/replacement/ or,
( . , . )s/regular expression/replacement/g
The substitute command searches each addressed
line for an occurrence of the specified regular
expression. On each line in which a match is
found, all matched strings are replaced by the
replacement specified, if the global replacement
indicator `g' appears after the command. If the
global indicator does not appear, only the first
occurrence of the matched string is replaced. It
is an error for the substitution to fail on all
addressed lines. Any character other than space
or new-line may be used instead of `/' to delimit
the regular expression and the replacement. `.'
is left at the last line substituted.
An ampersand `&' appearing in the replacement is
replaced by the regular expression that was
matched. The special meaning of `&' in this
context may be suppressed by preceding it by `\'.
(1,$)v/regular expression/command list
This command is the same as the global command
except that the command list is executed with `.'
initially set to every line except those matching
the regular expression.
(1,$)w filename
The write command writes the addressed lines onto
the given file. If the file does not exist, it is
created mode 666 (readable and writeable by
everyone). The remembered file name is not
changed unless `filename' is the very first file
name mentioned. If no file name is given, the
remembered file name, if any, is used (see e and f
commands). `.' is unchanged. If the command is
successful, the number of characters written is
typed.
($)=
The line number of the addressed line is typed.
`.' is unchanged by this command.
!UNIX command
The remainder of the line after the `!' is sent to
UNIX to be interpreted as a command. `.' is
unchanged. The entire shell syntax is not
recognized. See msh(VII) for the restrictions.
( .+1 )<newline>
An address alone on a line causes the addressed
line to be printed. A blank line alone is
equivalent to `.+1p'; it is useful for stepping
through text.
If an interrupt signal (ASCII DEL) is sent, ed will print a
`?' and return to its command level.
If invoked with the command name `-', (see init(VII)) ed
will sign on with the message `Editing system' and print `*'
as the command level prompt character.
Ed has size limitations on the maximum number of lines that
can be edited, on the maximum number of characters in a
line, in a global's command list, in a remembered file name,
and in the size of the temporary file. The current sizes
are: 4000 lines per file, 512 characters per line, 256
characters per global command list, 64 characters per file
name, and 64K characters in the temporary file (see BUGS).
FILES
/tmp/etm?, temporary
/etc/msh, to implement the `!' command.
DIAGNOSTICS
`?' for errors in commands; `TMP' for temporary file
overflow.
SEE ALSO
A Tutorial Introduction to the ED Text Editor (internal
memorandum)
BUGS
The temporary file can grow to no more than 64K bytes.