ED(C) UNIX System V
Name
ed, red - invokes the text editor
Syntax
ed [ - ] [ -p string ] [ file ]
red [ file ]
Description
ed is the standard text editor. If the file 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. ed operates on a copy of the file it
is editing; changes made to 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.
red is a restricted version of ed(C). It will only allow
editing of files in the current directory. It prohibits
executing sh(C) commands via the ! command. red displays an
error message on any attempt to bypass these restrictions.
In general, red does not allow commands like
!date
or
!sh
Furthermore, red will not allow pathnames in its command
line. For example, the command:
red /etc/passwd
when the current directory is not /etc causes an error.
Options
The options to ed are:
- Suppresses the printing of character counts by the e,
r, and w commands, of diagnostics from e and q
commands, and the ! prompt after a !shell command.
-p Allows the user to specify a prompt string.
ed supports formatting capability. After including a format
specification as the first line of file and invoking ed with
your terminal in stty -tabs or stty tab3 mode (see stty(C)),
the specified tab stops will automatically be used when
scanning file. For example, if the first line of a file
contained:
<:t5,10,15 s72:>
tab stops would be set at columns 5, 10, and 15, and a
maximum line length of 72 would be imposed. NOTE: While
inputing text, tab characters are expanded to every eighth
column as the default.
Commands to ed have a simple and regular structure: zero,
one, or two addresses followed by a single-character
command, possibly followed by parameters to that command.
These addresses specify one or more lines in the buffer.
Every command that requires addresses has default addresses,
so that the addresses can very 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 entering a period (.) alone at the
beginning of a line.
ed supports a limited form of regular expression notation;
regular expressions are used in addresses to specify lines
and in some commands (e.g., s) to specify portions of a line
that are to be substituted. A regular expression specifies
a set of character strings. 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:
The following one-character regular expressions match a
single character:
1.1 An ordinary character (not one of those discussed in
1.2 below) is a one-character regular expression that
matches itself.
1.2 A backslash (\) followed by any special character is
a one-character regular expression that matches the
special character itself. The special characters
are:
a. ., *, [, and \ (dot, star, left square bracket,
and backslash, respectively), which are
otherwise special, except when they appear
within square brackets ([]); see 1.4 below).
b. ^ (caret), which is special at the beginning of
an entire regular expression (see 3.1 and 3.2
below), or when it immediately follows the left
of a pair of square brackets ([]) (see 1.4
below).
c. $ (dollar sign), which is special at the end of
an entire regular expression (see 3.2 below).
d. The character used to bound (i.e., delimit) an
entire regular expression, which is special for
that regular expression (for example, see how
slash (/) is used in the g command below).
1.3 A period (.) is a one-character regular expression
that matches any character except newline.
1.4 A nonempty string of characters enclosed in square
brackets ([]) is a one-character regular expression
that matches any one character in that string. If,
however, the first character of the string is a caret
(^), the one-character regular expression matches any
character except newline and the remaining characters
in the string. The star (*) also has this special
meaning only if it occurs first in the string. The
dash (-) may be used to indicate a range of
consecutive ASCII characters; for example, [0-9] is
equivalent to [0123456789]. The dash (-) loses this
special meaning if it occurs first (after an initial
caret (^), if any) or last in the string. The right
square bracket (]) does not terminate such a string
when it is the first character within it (after an
initial caret (^), if any); e.g., []a-f] matches
either a right square bracket (]) or one of the
letters ``a'' through ``f'' inclusive. Dot, star,
left bracket, and the backslash lose their special
meaning within such a string of characters.
Ranges of characters (characters separated by -) are treated
according to the current locale's collation sequence (see
locale(M)). Therefore, if the collation sequence in use is
A, a, B, b, C, c, then the expression [a-d] is equivalent to
the expression [aBbCcDd].
To specify a collation item within a class, the item must be
enclosed between [. and .]. Two character to one collation
item mappings must be specified this way. For example, if
the current collation rules specify that the characters
``Ch'' map to one character for collation purposes (as in
Spanish), then this collation item would be specified as
[.Ch.].
To specify a group of collation items, which are classified
as equal unless all other collation items in the string also
match, in which case a secondary ``weight'' becomes
significant, a single member of that group must be enclosed
between [= and =]. For example, if the characters A and a
are in the same group then the class expressions [[=a=]b],
[[=A=]b] and [Aab] are all equivalent.
The ctype classes can also be specified within regular
expressions. These are enclosed between [: and :]. The
possible ctype classes are:
[:alpha:] Matches alphabetic characters
[:upper:] Matches upper case characters
[:lower:] Matches lower case characters
[:digit:] Matches digits
[:alnum:] Matches alphanumeric characters
[:space:] Matches white space
[:print:] Matches printable characters
[:punct:] Matches punctuation marks
[:graph:] Matches graphical characters
[:cntrl:] Matches control characters
The following rules may be used to construct regular
expressions from one-character regular expressions:
2.1 A one-character regular expression followed by a star
(*) is a regular expression that matches zero or more
occurrences of the one-character regular expression.
If there is any choice, the longest leftmost string
that permits a match is chosen.
2.2 A one-character regular expression followed by \{m\},
\{m,\}, or \{m,n\} is a regular expression that matches
a range of occurrences of the one-character regular
expression. The values of m and n must be nonnegative
integers less than 255; \{m\} matches exactly m
occurrences; \{m,\} matches at least m occurrences;
\{m,n\} matches any number of occurrences between m and
n, inclusive. Whenever a choice exists, the regular
expression matches as many occurrences as possible.
2.3 The concatenation of regular expressions is a regular
expression that matches the concatenation of the
strings matched by each component of the regular
expression.
2.4 A regular expression enclosed between the character
sequences \( and \) is a regular expression that
matches whatever the unadorned regular expression
matches. See 2.6 below for a discussion of why this is
useful.
2.5 The expression \n matches the same string of characters
as was matched by an expression enclosed between \( and
\) earlier in the same regular expression. Here n is a
digit; the subexpression specified is that beginning
with the n-th occurrence of \( counting from the left.
For example, the expression ^\(.*\)\1$ matches a line
consisting of two repeated appearances of the same
string.
Finally, an entire regular expression may be constrained to
match only an initial segment or final segment of a line (or
both):
3.1 A caret (^) at the beginning of an entire regular
expression constrains that regular expression to
match an initial segment of a line.
3.2 A dollar sign ($) at the end of an entire regular
expression constrains that regular expression to
match a final segment of a line. The construction
^entire regular expression$ constrains the entire
regular expression to match the entire line.
The null regular expression (e.g., //) is equivalent to the
last regular expression encountered.
To understand addressing in ed , it is necessary to know
that there is a current line at all times. Generally
speaking, the current line is the last line affected by a
command; the exact effect on the current line is discussed
under the description of each command. Addresses are
constructed as follows:
1. The character . addresses the current line.
2. The character $ addresses the last line of the
buffer.
3. A decimal number n addresses the n-th line of the
buffer.
4. 'x addresses the line marked with the mark name
character x, which must be a lowercase letter. Lines
are marked with the k command described below.
5. A regular expression enclosed by slashes (/)
addresses the first line found by searching forward
from the line following the current line 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 and continues up to and
including the current line, so that the entire buffer
is searched.
6. A regular expression enclosed in question marks (?)
addresses the first line found by searching backward
from the line preceding the current line toward the
beginning of the buffer and stopping at the first
line containing a string matching the regular
expression. If necessary, the search wraps around to
the end of the buffer and continues up to and
including the current line. See also the last
paragraph before Files below.
7. An address followed by a plus sign (+) or a minus
sign (-) followed by a decimal number specifies that
address plus or minus the indicated number of lines.
The plus sign may be omitted.
8. If an address begins with + or -, the addition or
subtraction is taken with respect to the current
line; e.g, -5 is understood to mean .-5.
9. If an address ends with + or -, then 1 is added to or
subtracted from the address, respectively. As a
consequence of this rule and of rule 8 immediately
above, the address - refers to the line preceding the
current line. (To maintain compatibility with
earlier versions of the editor, the character ^ in
addresses is entirely equivalent to -.) Moreover,
trailing + and - characters have a cumulative effect,
so -- refers to the current line less 2.
10. For convenience, a comma (,) stands for the address
pair 1,$, while a semicolon (;) stands for the pair
.,$.
Commands may require zero, one, or two addresses. Commands
that require no addresses regard the presence of an address
as an error. Commands that accept one or two addresses
assume default addresses when an insufficient number of
addresses is given; if more addresses are given than such a
command requires, the last address(es) are used.
Typically, addresses are separated from each other by a
comma (,). They may also be separated by a semicolon (;).
In the latter case, the current line (.) is set to the first
address, and only then is the second address calculated.
This feature can be used to determine the starting line for
forward and backward searches (see rules 5 and 6 above).
The second address of any two-address sequence must
correspond to a line that follows, in the buffer, 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.
It is generally illegal for more than one command to appear
on a line. However, any command (except e, f, r, or w) may
be suffixed by p or by l, in which case the current line is
either printed or listed, respectively, as discussed below
under the p and l commands.
(.)a
<text>
.
The append command reads the given text and appends it
after the addressed line; dot is left at the address of
the last inserted line, or, if there were no inserted
lines, at the addressed line. Address 0 is legal for
this command: it causes the ``appended'' text to be
placed at the beginning of the buffer.
(.)c
<text>
.
The change command deletes the addressed lines, then
accepts input text that replaces these lines; dot is
left at the address of the last line input, or, if
there were none, at the first line that was not
deleted.
(.,.)d
The delete command deletes the addressed lines from the
buffer. The line after the last line deleted becomes
the current line; if the lines deleted were originally
at the end of the buffer, the new last line becomes the
current line.
e file
The edit command causes the entire contents of the
buffer to be deleted, and then the named file to be
read in; dot is set to the last line of the buffer. If
no filename is given, the currently remembered
filename, if any, is used (see the f command). The
number of characters read is typed. file is remembered
for possible use as a default filename in subsequent e,
r, and w commands. If file begins with an exclamation
(!), the rest of the line is taken to be a shell
command. The output of this command is read for the e
and r commands. For the w command, the file is used as
the standard input for the specified command. Such a
shell command is not remembered as the current
filename.
E file
The Edit command is like e, except the editor does not
check to see if any changes have been made to the
buffer since the last w command.
f file
If file is given, the filename command changes the
currently remembered filename to file; otherwise, it
prints the currently remembered filename.
(1,$)g/regular-expression/command list
In the global command, the first step is to mark every
line that matches the given regular expression. Then,
for every such line, the given command list is executed
with . initially set to that line. A single command or
the first of a list of commands appears on the same
line as the global command. All lines of a multiline
list except the last line must be ended with a \; a, i,
and c commands and associated input are permitted; the
. terminating input mode may be omitted if it would be
the last line of the command list. An empty command
list is equivalent to the p command. The g, G, v, and
V commands are not permitted in the command list. See
also Notes and the last paragraph before Files below.
(1,$)G/regular-expression/
In the interactive Global command, the first step is to
mark every line that matches the given regular
expression. Then, for every such line, that line is
printed, dot (.) is changed to that line, and any one
command (other than one of the a, c, i, g, G, v, and V
commands) may be input and is executed. After the
execution of that command, the next marked line is
printed, and so on. A newline acts as a null command.
An ampersand (&) causes the re-execution of the most
recent command executed within the current invocation
of G. Note that the commands input as part of the
execution of the G command may address and affect any
lines in the buffer. The G command can be terminated
by entering an INTERRUPT (pressing the DEL key).
h
The help command gives a short error message that
explains the reason for the most recent ? diagnostic.
H
The Help command causes ed to enter a mode in which
error messages are printed for all subsequent ?
diagnostics. It will also explain the previous
diagnostic if there was one. The H command alternately
turns this mode on and off. It is initially off.
(.)i
<text>
.
The insert command inserts the given text before the
addressed line; dot is left at the address of the last
inserted line, or if there were no inserted lines, at
the addressed line. This command differs from the a
command only in the placement of the input text.
Address 0 is not legal for this command.
(.,.+1)j
The join command joins contiguous lines by removing the
appropriate newline characters. If only one address is
given, this command does nothing.
(.)kx
The mark command marks the addressed line with name x,
which must be a lowercase letter. The address 'x then
addresses this line. Dot is unchanged.
(.,.)l
The list command prints the addressed lines in an
unambiguous way: a few nonprinting characters (e.g.,
tab, backspace) are represented by mnemonic
overstrikes, all other nonprinting characters are
printed in octal, and long lines are folded. An l
command may be appended to any command other than e, f,
r, or w.
(.,.)ma
The move command repositions the addressed line(s)
after the line addressed by a. Address 0 is legal for
a and causes the addressed line(s) to be moved to the
beginning of the file. It is an error if address a
falls within the range of moved lines. Dot is left at
the last line moved.
(.,.)n
The number command prints the addressed lines,
preceding each line by its line number and a tab
character. Dot is left at the last line printed. The
n command may be appended to any command other than e,
f, r, or w.
(.,.)p
The print command prints the addressed lines. Dot is
left at the last line printed. The p command may be
appended to any command other than e, f, r, or w; for
example, dp deletes the current line and prints the new
current line.
P
The editor will prompt with a * for all subsequent
commands. The P command alternately turns this mode on
and off. It is initially off.
q
The quit command causes ed to exit. No automatic write
of a file is done.
Q
The editor exits without checking if changes have been
made in the buffer since the last w command.
($)r file
The read command reads in the given file after the
addressed line. If no filename is given, the currently
remembered filename, if any, is used (see e and f
commands). The currently remembered filename is not
changed unless file is the very first filename
mentioned since ed was invoked. 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. Dot is set to the address of
the last line read in. If file begins with !, the rest
of the line is taken to be a shell command whose output
is to be read. Such a shell command is not remembered
as the current filename.
(.,.)s/regular-expression/replacement/ or
(.,.)s/regular-expression/replacement/g or
(.,.)s/regular-expression/replacement/n n=1-512
The substitute command searches each addressed line for
an occurrence of the specified regular expression. In
each line in which a match is found, all nonoverlapped
matched strings are replaced by replacement 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
newline may be used instead of / to delimit regular-
expression and replacement. Dot is left at the address
of the last line on which a substitution occurred.
The n character represents any number between one and
512. This number indicates the instance of the pattern
to be replaced on each addressed line.
An ampersand (&) appearing in replacement is replaced
by the string matching the regular-expression on the
current line. The special meaning of the ampersand in
this context may be suppressed by preceding it with a
backslash. The characters \n, where n is a digit, are
replaced by the text matched by the n-th regular
subexpression of the specified regular expression
enclosed between \( and \). When nested parenthesized
subexpressions are present, n is determined by counting
occurrences of \( starting from the left. When the
character % is the only character in replacement, the
replacement used in the most recent substitute command
is used as the replacement in the current substitute
command. The % loses its special meaning when it is in
a replacement string of more than one character or when
it is preceded by a \.
A line may be split by substituting a newline character
into it. The newline in the replacement must be
escaped by preceding it with a \. Such a substitution
cannot be done as part of a g or v command list.
(.,.)ta
This command acts just like the m command, except that
a copy of the addressed lines is placed after address a
(which may be 0). Dot is left at the address of the
last line of the copy.
u
The undo command nullifies the effect of the most
recent command that modified anything in the buffer,
namely the most recent a, c, d, g, i, j, m, r, s, t, v,
G, or V command.
(1,$)v/regular-expression/command list
This command is the same as the global command g except
that the command list is executed with dot initially
set to every line that does not match the regular
expression.
(1,$)V/regular-expression/
This command is the same as the interactive global
command G except that the lines that are marked during
the first step are those that do not match the regular
expression.
(1,$)w file
The write command writes the addressed lines into the
named file. If the file does not exist, it is created
with mode 666 (readable and writeable by everyone),
unless the umask setting (see sh(C)) dictates
otherwise. The currently remembered filename is not
changed unless file is the very first filename
mentioned since ed was invoked. If no filename is
given, the currently remembered filename, if any, is
used (see e and f commands), and dot remains. If the
command is successful, the number of characters written
is displayed. If file begins with an exclamation (!),
the rest of the line is taken to be a shell command to
which the addressed lines are supplied as the standard
input. Such a shell command is not remembered as the
current filename.
($)=
The line number of the addressed line is typed. Dot is
unchanged by this command.
!shell command
The remainder of the line after the ! is sent to the
UNIX shell (sh(C)) to be interpreted as a command.
Within the text of that command, the unescaped
character % is replaced with the remembered filename.
If a ! appears as the first character of the shell
command, it is replaced with the text of the previous
shell command. Thus, !! will repeat the last shell
command. If any expansion is performed, the expanded
line is echoed. Dot is unchanged.
(.+1)
An address alone on a line causes the addressed line to
be printed. A RETURN alone on a line is equivalent to
.+1p. This is useful for stepping forward through the
editing buffer a line at a time.
If an interrupt signal (ASCII DEL or BREAK) is sent, ed
prints a question mark (?) and returns to its command level.
ed has size limitations: 512 characters per line, 256
characters per global command list, 64 characters per
filename, and 128K characters in the buffer. The limit on
the number of lines depends on the amount of user memory.
When reading a file, ed discards ASCII NUL characters and
all characters after the last newline. Files (e.g., a.out)
that contain characters not in the ASCII set (bit 8 on)
cannot be edited by ed.
If the closing delimiter of a regular expression or of a
replacement string (e.g., /) would be the last character
before a newline, that delimiter may be omitted, in which
case the addressed line is printed. Thus, the following
pairs of commands are equivalent:
s/s1/s2 s/s1/s2/p
g/s1 g/s1/p
?s1 ?s1?
Files
/tmp/e# Temporary; # is the process number
ed.hup Work is saved here if the terminal is hung up
See Also
coltbl(M), grep(C), locale(M), sed(C), sh(C), stty(C),
regexp(S)
Diagnostics
? Command errors
? file An inaccessible file
Use the help and Help commands for detailed explanations.
If changes have been made in the buffer since the last w
command that wrote the entire buffer, ed warns the user if
an attempt is made to destroy ed's buffer via the e or q
commands by printing ? and allowing you to continue editing.
A second e or q command at this point will take effect. The
dash (-) command-line option inhibits this feature.
Notes
An exclamation (!) command cannot be subject to a g or a v
command.
The ! command and the ! escape from the e, r, and w commands
cannot be used if the the editor is invoked from a
restricted shell (see sh(C)).
The sequence \n in a regular expression does not match any
character.
The l command mishandles DEL.
Because 0 is an illegal address for the w command, it is not
possible to create an empty file with ed.
If the editor input is coming from a command file (i.e., ed
file < ed-cmd-file), the editor will exit at the first
failure of a command in the command file.
Standards Conformance
ed is conformant with:
AT&T SVID Issue 2, Select Code 307-127;
and The X/Open Portability Guide II of January 1987.
(printed 8/28/89) ED(C)