ed(1) (Essential Utilities) ed(1)
NAME
ed, red - text editor
SYNOPSIS
ed [-s] [-p string ] [-x] [-C] [file]
red [-s] [-p string ] [-x] [-C] [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.
-s Suppresses the printing of character counts by e, r, and w
commands, of diagnostics from e and q commands, and of the !
prompt after a !shell command.
-p Allows the user to specify a prompt string.
-x Encryption option; when used, ed simulates an X command and
prompts the user for a key. This key is used to encrypt and
decrypt text using the algorithm of crypt(1). The X command
makes an educated guess to determine whether text read in is
encrypted or not. The temporary buffer file is encrypted also,
using a transformed version of the key typed in for the -x
option. See crypt(1). Also, see the NOTES section at the end
of this manual page.
-C Encryption option; the same as the -x option, except that ed
simulates a C command. The C command is like the X command,
except that all text read in is assumed to have been encrypted.
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. It will only allow editing of
files in the current directory. It prohibits executing shell
commands via !shell command. Attempts to bypass these restrictions
result in an error message (restricted shell).
Both ed and red support the fspec(4) 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(1)], 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: when you are entering text into
the file, this format is not in effect; instead, because of being in
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stty -tabs or stty tab3 mode, tabs are expanded to every eighth
column.
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. Leave input mode by typing a period (.) at the
beginning of a line, followed immediately by a carriage return.
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 (RE) specifies a set of character
strings. A member of this set of strings is said to be matched by
the RE. The REs allowed by ed are constructed as follows:
The following one-character REs match a single character:
1.1 An ordinary character (not one of those discussed in 1.2
below) is a one-character RE that matches itself.
1.2 A backslash (\) followed by any special character is a one-
character RE that matches the special character itself. The
special characters are:
a. ., *, [, and \ (period, asterisk, left square bracket,
and backslash, respectively), which are always special,
except when they appear within square brackets ([]; see
1.4 below).
b. ^ (caret or circumflex), which is special at the
beginning of an entire RE (see 4.1 and 4.3 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 RE (see 4.2 below).
d. The character used to bound (i.e., delimit) an entire
RE, which is special for that RE (for example, see how
slash (/) is used in the g command, below.)
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1.3 A period (.) is a one-character RE that matches any character
except new-line.
1.4 A non-empty string of characters enclosed in square brackets
([]) is a one-character RE that matches any one character in
that string. If, however, the first character of the string
is a circumflex (^), the one-character RE matches any
character except new-line and the remaining characters in the
string. The ^ has this special meaning only if it occurs
first in the string. The minus (-) may be used to indicate a
range of consecutive characters; for example, [0-9] is
equivalent to [0123456789]. The - loses this special meaning
if it occurs first (after an initial ^, 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 ^, if any); e.g., []a-f] matches either a right square
bracket (]) or one of the ASCII letters a through f inclusive.
The four characters listed in 1.2.a above stand for themselves
within such a string of characters.
The following rules may be used to construct REs from one-character
REs:
2.1 A one-character RE is a RE that matches whatever the one-
character RE matches.
2.2 A one-character RE followed by an asterisk (*) is a RE that
matches zero or more occurrences of the one-character RE. If
there is any choice, the longest leftmost string that permits
a match is chosen.
2.3 A one-character RE followed by \{m\}, \{m,\}, or \{m,n\} is a
RE that matches a range of occurrences of the one-character
RE. The values of m and n must be non-negative integers less
than 256; \{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 RE matches as many occurrences as possible.
2.4 The concatenation of REs is a RE that matches the
concatenation of the strings matched by each component of the
RE.
2.5 A RE enclosed between the character sequences \( and \) is a
RE that matches whatever the unadorned RE matches.
2.6 The expression \n matches the same string of characters as was
matched by an expression enclosed between \( and \) earlier in
the same RE. Here n is a digit; the sub-expression specified
is that beginning with the n-th occurrence of \( counting from
the left. For example, the expression ^\(.*\)\1$ matches a
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line consisting of two repeated appearances of the same
string.
A RE may be constrained to match words.
3.1 \< constrains a RE to match the beginning of a string or to
follow a character that is not a digit, underscore, or letter.
The first character matching the RE must be a digit,
underscore, or letter.
3.2 \> constrains a RE to match the end of a string or to precede
a character that is not a digit, underscore, or letter.
An entire RE may be constrained to match only an initial segment or
final segment of a line (or both).
4.1 A circumflex (^) at the beginning of an entire RE constrains
that RE to match an initial segment of a line.
4.2 A dollar sign ($) at the end of an entire RE constrains that
RE to match a final segment of a line.
4.3 The construction ^entire RE$ constrains the entire RE to match
the entire line.
The null RE (e.g., //) is equivalent to the last RE encountered. See
also the last paragraph before FILES below.
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; the exact effect on the
current line is discussed under the description of each command.
Addresses are constructed as follows:
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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 an ASCII lower-case letter (a-z). Lines are
marked with the k command described below.
5. A RE 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 RE. 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. See also the last paragraph before FILES below.
6. A RE 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 RE. 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
(respectively minus) the indicated number of lines. A
shorthand for .+5 is .5.
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
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are given than such a command requires, the last one(s) 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 first address is calculated, the current line (.) is set to that
value, and then the second address is 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 in the buffer that follows
the line corresponding to the first address.
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In the following list of ed commands, the parentheses shown prior to
the command are not part of the address; rather they show the default
address(es) for the command.
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
l, n, or p in which case the current line is either listed, numbered
or printed, respectively, as discussed below under the l, n, and p
commands.
(.)a
<text>
.
The append command accepts zero or more lines of text and
appends it after the addressed line in the buffer. The current
line (.) is left at the last inserted line, or, if there were
none, 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. The maximum number of characters that
may be entered from a terminal is 256 per line (including the
new-line character).
(.)c
<text>
.
The change command deletes the addressed lines from the buffer,
then accepts zero or more lines of text that replaces these
lines in the buffer. The current line (.) is left at the last
line input, or, if there were none, at the first line that was
not deleted.
C
Same as the X command, described later, except that ed assumes
all text read in for the e and r commands is encrypted unless a
null key is typed in.
(.,.)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 deletes the entire contents of the buffer and
then reads the contents of file into the buffer. The current
line (.) is set to the last line of the buffer. If file is not
given, the currently remembered file name, if any, is used (see
the f command). The number of characters read in is printed;
file is remembered for possible use as a default file name in
subsequent e, r, and w commands. If file is replaced by !, the
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rest of the line is taken to be a shell [sh(1)] command whose
output is to be read in. Such a shell command is not
remembered as the current file name. See also DIAGNOSTICS
below.
E file
The Edit command is like e, except that 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 file-name command changes the currently
remembered file name to file; otherwise, it prints the
currently remembered file name.
(1,$)g/RE/command list
In the global command, the first step is to mark every line
that matches the given RE. Then, for every such line, the
given command list is executed with the current line (.)
initially set to that line. A single command or the first of a
list of commands appears on the same line as the global
command. All lines of a multi-line list except the last line
must be ended with a \; a, i, and c commands and associated
input are permitted. The . terminating input mode may be
omitted if it would be the last line of the command list. An
empty command list is equivalent to the p command. The g, G,
v, and V commands are not permitted in the command list. See
also the NOTES and the last paragraph before FILES below.
(1,$)G/RE/
In the interactive Global command, the first step is to mark
every line that matches the given RE. Then, for every such
line, that line is printed, the current line (.) 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 new-line acts as a null command; an & 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 an
interrupt signal (ASCII DEL or BREAK).
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 ? if there was one. The H command
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alternately turns this mode on and off; it is initially off.
(.)i
<text>
.
The insert command accepts zero or more lines of text and
inserts it before the addressed line in the buffer. The
current line (.) is left at the last inserted line, or, if
there were none, 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. The maximum number of
characters that may be entered from a terminal is 256 per line
(including the new-line character).
(.,.+1)j
The join command joins contiguous lines by removing the
appropriate new-line characters. If exactly one address is
given, this command does nothing.
(.)kx
The mark command marks the addressed line with name x, which
must be an ASCII lower-case letter (a-z). The address 'x then
addresses this line; the current line (.) is unchanged.
(.,.)l
The list command prints the addressed lines in an unambiguous
way: a few non-printing characters (e.g., tab, backspace) are
represented by visually mnemonic overstrikes. All other non-
printing 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;
the current line (.) 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; the current line
(.) 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; the current line
(.) 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.
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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; however, see DIAGNOSTICS , below.
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 the contents of file into the buffer.
If file is not given, the currently remembered file name, if
any, is used (see the e and f commands). The currently
remembered file name is not changed unless file is the very
first file name mentioned since ed was invoked. Address 0 is
legal for r and causes the file to be read in at the beginning
of the buffer. If the read is successful, the number of
characters read in is printed; the current line (.) is set to
the last line read in. If file is replaced by !, the rest of
the line is taken to be a shell [see sh(1)] command whose
output is to be read in. For example, $r !ls appends current
directory to the end of the file being edited. Such a shell
command is not remembered as the current file name.
(.,.)s/RE/replacement/ or
(.,.)s/RE/replacement/g or
(.,.)s/RE/replacement/n n = 1-512
The substitute command searches each addressed line for an
occurrence of the specified RE. In each line in which a match
is found, all (non-overlapped) matched strings are replaced by
the 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.
If a number n, appears after the command, only the n-th
occurrence of the matched string on each addressed line is
replaced. It is an error if the substitution fails on all
addressed lines. Any character other than space or new-line
may be used instead of / to delimit the RE and the replacement;
the current line (.) is left at the last line on which a
substitution occurred. See also the last paragraph before
FILES below.
An ampersand (&) appearing in the replacement is replaced by
the string matching the RE on the current line. The special
meaning of & in this context may be suppressed by preceding it
by \. As a more general feature, the characters \n, where n is
a digit, are replaced by the text matched by the n-th regular
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subexpression of the specified RE 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 the
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 is preceded by
a \.
A line may be split by substituting a new-line character into
it. The new-line in the replacement must be escaped by
preceding it by \. Such 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); the current line (.) is left at the last line copied.
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,$)v/RE/command list
This command is the same as the global command g, except that
the lines marked during the first step are those that do not
match the RE.
(1,$)V/RE/
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 RE.
(1,$)w file
The write command writes the addressed lines into file. If
file does not exist, it is created with mode 666 (readable and
writable by everyone), unless your file creation mask dictates
otherwise; see the description of the umask special command on
sh(1). The currently remembered file name is not changed
unless file is the very first file name mentioned since ed was
invoked. If no file name is given, the currently remembered
file name, if any, is used (see the e and f commands); the
current line (.) is unchanged. If the command is successful,
the number of characters written is printed. If file is
replaced by !, the rest of the line is taken to be a shell [see
sh(1)] command whose standard input is the addressed lines.
Such a shell command is not remembered as the current file
name.
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(1,$)W file
This command is the same as the write command above, except
that it appends the addressed lines to the end of file if it
exists. If file does not exist, it is created as described
above for the w command.
X
A key is prompted for, and it is used in subsequent e, r, and w
commands to decrypt and encrypt text using the crypt(1)
algorithm. An educated guess is made to determine whether text
read in for the e and r commands is encrypted. A null key
turns off encryption. Subsequent e, r, and w commands will use
this key to encrypt or decrypt the text [see crypt(1)]. An
explicitly empty key turns off encryption. Also, see the -x
option of ed.
($)=
The line number of the addressed line is typed; the current
line (.) is unchanged by this command.
!shell command
The remainder of the line after the ! is sent to the UNIX
system shell [see sh(1)] to be interpreted as a command.
Within the text of that command, the unescaped character % is
replaced with the remembered file name; 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; the current line (.) is unchanged.
(.+1)<new-line>
An address alone on a line causes the addressed line to be
printed. A new-line alone is equivalent to .+1p; it is useful
for stepping forward through the buffer.
If an interrupt signal (ASCII DEL or BREAK) is sent, ed prints a ?
and returns to its command level.
Some size limitations: 512 characters in a line, 256 characters in a
global command list, and 64 characters in the pathname of a file
(counting slashes). The limit on the number of lines depends on the
amount of user memory: each line takes 1 word.
When reading a file, ed discards ASCII NUL characters.
If a file is not terminated by a new-line character, ed adds one and
puts out a message explaining what it did.
If the closing delimiter of a RE or of a replacement string (e.g., /)
would be the last character before a new-line, that delimiter may be
omitted, in which case the addressed line is printed. The following
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ed(1) (Essential Utilities) ed(1)
pairs of commands are equivalent:
s/s1/s2 s/s1/s2/p
g/s1 g/s1/p
?s1 ?s1?
FILES
$TMPDIR if this environmental variable is not null, its value is
used in place of /var/tmp as the directory name for the
temporary work file.
/var/tmp if /var/tmp exists, it is used as the directory name for
the temporary work file.
/tmp if the environmental variable TMPDIR does not exist or is
null, and if /var/tmp does not exist, then /tmp is used
as the directory name for the temporary work file.
ed.hup work is saved here if the terminal is hung up.
SEE ALSO
edit(1), ex(1), grep(1), sed(1), sh(1), stty(1), umask(1), vi(1).
fspec(4), regexp(5) in the Programmer's Reference Manual.
DIAGNOSTICS
? for command errors.
?file for 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. It prints ? and allows
one to continue editing. A second e or q command at this point will
take effect. The -s command-line option inhibits this feature.
NOTES
The - option, although it continues to be supported, has been
replaced in the documentation by the -s option that follows the
Command Syntax Standard [see intro(1)].
The encryption options and commands are provided with the Security
Administration Utilities package, which is available only in the
United States.
A ! 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 editor is invoked from a restricted shell [see sh(1)].
The sequence \n in a RE does not match a new-line character.
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If the editor input is coming from a command file (e.g., ed file <
ed_cmd_file), the editor exits at the first failure.
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