6/12/72 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 command 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 an explicit 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 struc-
ture: zero or more addresses followed by a single
character command, possibly followed by parame-
ters 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 fol-
lows:
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 reg-
ular expression matches the null character
at the beginning of a line.
3. A currency symbol ($) at the end of a regu-
lar expression matches the null character
at the end of a line.
4. A period (.) matches any character but a
new-line character.
5. A regular expression followed by an aster-
isk (*) matches any number of adjacent oc-
currences (including zero) of the regular
expression it follows.
6. A string of characters enclosed in square
brackets ([]) matches any character in the
string but no others. If, however, the
first character of the string is a circum-
flex (^) the regular expression matches any
character but new-line and the characters
in the string.
7. The concatenation of regular expressions is
a regular expression which matches the con-
catenation of the strings matched by the
components of the regular expression.
8. The null regular expression standing alone
is equivalent to the last regular expres-
sion encountered.
Regular expressions are used in addresses to
specify lines and in one command (s, see below)
to specify a portion of a line which is to be re-
placed.
If it is desired to use one of the regular ex-
pression metacharacters as an ordinary character,
that character may be preceded by "\". This also
applies to the character bounding the regular ex-
pression (often "/") and to "\" itself.
Addresses are constructed as follows. To under-
stand addressing in ed it is necessary to know
that at any time there is a current line. Gener-
ally speaking, the current line is the last line
affected by a command; however, the exact effect
on the current line by each command is discussed
under the description of the command.
1. The character "." addresses the current
line.
2. The character "^" addresses the line imme-
diately before the current line.
3. The character "$" 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
"/" 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.
5. 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.
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 number 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 printable character. Lines may be
marked with the "k" command described be-
low.
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 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 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 ad-
dress 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 paren-
theses 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 re-
places 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,$)g/regular expression/command list
In the global command, the first step is to
mark every line which matches the given
regular expression. Then for every such
line, the given command list is executed
with "." initially set to that line. A
single command or the first of multiple
commands appears on the same line with the
global command. All lines of a multi-line
list except the last line must be ended
with "\". a, i, and c commands and associ-
ated input are permitted; the "." terminat-
ing input mode may be omitted if it would
be on the last line of the command list.
The (global) commands, g and v, are not
permitted in the command list.
(.)i
<text>
.
This command inserts the given text before
the addressed line. "." is left at the
last line input; if there were none, at the
addressed line. This command differs from
the a command only in the placement of the
text.
(.)kx
The mark command associates or marks the
addressed line with the single character
mark name "x". The ten most recent mark
names are remembered. The current mark
names may be printed with the n command.
(.,.)l
The list command prints the addressed lines
in an unambiguous way. Non-printing char-
acters are over-struck as follows:
char prints
bs \
tab >
ret <
SI I
SO O
All character preceded by a prefix (ESC)
character are printed over-struck with ^
without the prefix. Long lines are folded
with the sequence \newline.
(.,.)mA
The move command will reposition the ad-
dressed lines after the line addressed by
"A". The line originally after the last
line moved becomes the current line; if the
lines moved were originally at the end, the
new last line becomes the current line.
n
The marknames command will print the cur-
rent mark names.
(.,.)p
The print command prints the addressed
lines. "." is left at the last line
printed. The p command may be placed on
the same line after any command.
q
The quit command causes ed to exit. No au-
tomatic write of a file is done.
($)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 remem-
bered 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 ad-
dressed line for an occurrence of the spec-
ified 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" ap-
pears after the command. If the global in-
dicator does not appear, only the first oc-
currence of the matched string is replaced.
It is an error for the substitution to fail
on all addressed lines. Any character oth-
er than space or new-line may be used in-
stead of "/" to delimit the regular expres-
sion and the replacement. "." is left at
the last line substituted.
The ampersand "&" appearing in the replace-
ment is replaced by the regular expression
that was matched. The special meaning of
"&" in this context may be suppressed by
preceding it by "\".
(1,$)v/regular expression/command list
This command is the same as the global com-
mand except that the command list is exe-
cuted with "." initially set to every line
except those matching the regular expres-
sion
(1,$)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 everyone). The
remembered file name is not changed unless
"filename" is the very first file name men-
tioned. If no file name is given, the re-
membered file name, if any, is used (see e
and f commands). "." is unchanged. If the
command is successful, the number of char-
acters 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 com-
mand. "." is unchanged.
(.+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 charac-
ter.
Ed has size limitations on the maximum number of
lines that can be edited, and on the maximum num-
ber of characters in a line, in a global's com-
mand list, and in a remembered 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 men-
tioned items is; 1300 - 4000 lines per file,
256 - 512 characters per line, 63 - 256 charac-
ters per global command list, and 64 characters
per file name.
FILES /tmp/etm? temporary
/etc/msh to implement the "!" command.
SEE ALSO --
DIAGNOSTICS "?" for any error
BUGS --
OWNER ken, dmr, jfo