ED (I) 1/15/73 ED (I)
NAME
ed -- editor
SYNOPSIS
ed [ name ]
DESCRIPTION
ed is the standard text editor.
If the optional argument is given, ed simulates an e com-
mand on the named file; that is to say, the file is read
into ed's buffer so that it can be edited.
ed operates on a copy of any file it is editing; changes
made in the copy have no effect on the file until a write
(w) 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. Cer-
tain 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 mere-
ly collected. Input mode is left by typing a period (.)
alone at the beginning of a line.
ed supports a limited form of regular expression nota-
tion. A regular expression is an expression which speci-
fies a set of strings of characters. A member of this
set of strings is said to be matched by the regular ex-
pression. The regular expressions allowed by ed are con-
structed 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 ex-
pression matches the null character at the begin-
ning of a line.
3. A currency symbol ($) at the end of a regular ex-
pression matches the null character at the end of a
line.
4. A period (.) matches any character but a new-line
character.
5. A regular expression followed by an asterisk (*)
matches any number of adjacent occurrences (includ-
ing zero) of the regular expression it follows.
6. A string of characters enclosed in square brackets
([]) matches any character in the string but no
others. If, however, the first character of the
string is a circumflex (^) the regular expression
matches any character but new-line and the charac-
ters in the string.
7. The concatenation of regular expressions is a regu-
lar expression which matches the concatenation of
the strings matched by the components of the regu-
lar expression.
8. The null regular expression standing alone is
equivalent to the last regular expression encoun-
tered.
Regular expressions are used in addresses to specify
lines and in one command (s, see below) to specify a por-
tion of a line which is to be replaced.
If it is desired to use one of the regular expression
metacharacters as an ordinary character, that character
may be preceded by "\". This also applies to the charac-
ter bounding the regular expression (often "/") and to
"\" itself.
Addresses are constructed as follows. To understand ad-
dressing in ed it is necessary to know that at any time
there is a current line. Generally speaking, the current
line is the last line affected by a command; however, the
exact effect on the current line by each command is dis-
cussed under the description of the command.
1. The character "." addresses the current line.
2. The character "^" addresses the line immediately
before the current line.
3. The character "$" addresses the last line of the
buffer.
4. A decimal number n addresses the nth line of the
buffer.
6. A regular expression enclosed in slashes "/" ad-
dresses the first line found by searching toward
the end of the buffer and stopping at the first
line containing a string matching the regular ex-
pression. If necessary the search wraps around to
the beginning of the buffer.
5. A regular expression enclosed in queries "?" ad-
dresses 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.
7. An address followed by a plus sign "+" or a minus
sign "-" followed by a decimal number specifies
that address plus (resp. minus) the indicated num-
ber of lines. The plus sign may be omitted.
8. "'x" addresses the line associated (marked) with
the mark name character "x" which must be a print-
able character. Lines may be marked with the "k"
command described below.
Commands may require zero, one, or two addresses. Com-
mands 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 ac-
cepted) 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 ad-
dress.
In the following list of ed commands, the default ad-
dresses 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 de-
fault file name in a subsequent r or w command.
f filename
The filename command prints the currently remem-
bered file name. If "filename" is given, the cur-
rently remembered file name is changed to "file-
name".
(1,$)g/regular expression/command list
In the global command, the first step is to mark
every line which matches the given regular expres-
sion. Then for every such line, the given command
list is executed with "." initially set to that
line. A single command or the first of multiple
commands appears on the same line with the global
command. All lines of a multi-line list except the
last line must be ended with "\". a, i, and c com-
mands and associated input are permitted; the "."
terminating input mode may be omitted if it would
be on the last line of the command list. The (glo-
bal) commands, g and v, are not permitted in the
command list.
(.)i
<text>
This command inserts the given text before the ad-
dressed line. "." is left at the last line input;
if there were none, at the addressed line. This
command differs from the a command only in the
placement of the text.
(.)kx
The mark command associates or marks the addressed
line with the single character mark name "x". The
ten most recent mark names are remembered. The
current mark names may be printed with the n com-
mand.
(.,.)mA
The move command will reposition the addressed
lines after the line addressed by "A". The line
originally after the last line moved becomes the
current line; if the lines moved were originally at
the end, the new last line becomes the current
line.
n
The marknames command will print the current mark
names.
(.,.)p
The print command prints the addressed lines. "."
is left at the last line printed. The p command
may be placed on the same line after any command.
q
The quit command causes ed to exit. No automatic
write of a file is done.
($)r filename
The read command reads in the given file after the
addressed line. If no file name is given, the re-
membered 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 men-
tioned. 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 expres-
sion. 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.
The ampersand "&" appearing in the replacement is
replaced by the regular expression that was
matched. The special meaning of "&" in this con-
text may be suppressed by preceding it by "\".
(1,$)v/regular expression/command list
This command is the same as the global command ex-
cept that the command list is executed with "."
initially set to every line except those matching
the regular expression
(1,$)w filename
The write command writes the addressed lines onto
the given file. If the file does not exist, it is
created mode 17 (readable and writeable by every-
one). The remembered file name is not changed un-
less "filename" is the very first file name men-
tioned. 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 un-
changed.
(.+1)<newline>
An address alone on a line causes that 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) 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, and on the maximum number of charac-
ters in a line, in a global's command list, and in a re-
membered file name. These limitations vary with the
physical core size of the PDP11 computer on which ed is
being used. The range of limiting sizes for the above
mentioned items is; 1300 - 4000 lines per file, 256 - 512
characters per line, 63 - 256 characters per global com-
mand list, and 64 characters per file name.
FILES
/tmp/etm? temporary
/etc/msh to implement the "!" command.
SEE ALSO --
DIAGNOSTICS "?" for any error
BUGS --