ED(1)ED(1)NAMEed - text editor
SYNOPSISed [ - ] [ -x ] [ 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. If -x is present, an x command is simulated
first to handle an encrypted file. The optional - suppresses the
printing of explanatory output and should be used when the standard
input is an editor script.
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.
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. Missing addresses are supplied by default.
In general, only one command may appear on a line. Certain commands
allow the addition of text to 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 specifies a set of strings of characters. A member of this
set of strings is said to be matched by the regular expression. In the
following specification for regular expressions the word `character'
means any character but newline.
1. Any character except a special character matches itself.
Special characters are the regular expression delimiter plus \[.
and sometimes ^*$.
2. A . matches any character.
3. A \ followed by any character except a digit or () matches that
character.
4. A nonempty string s bracketed [s] (or [^s]) matches any
character in (or not in) s. In s, \ has no special meaning, and
] may only appear as the first letter. A substring a-b, with a
and b in ascending ASCII order, stands for the inclusive range
of ASCII characters.
5. A regular expression of form 1-4 followed by * matches a
sequence of 0 or more matches of the regular expression.
6. A regular expression, x, of form 1-8, bracketed \(x\) matches
what x matches.
7. A \ followed by a digit n matches a copy of the string that the
bracketed regular expression beginning with the nth \( matched.
8. A regular expression of form 1-8, x, followed by a regular
expression of form 1-7, y matches a match for x followed by a
match for y, with the x match being as long as possible while
still permitting a y match.
9. A regular expression of form 1-8 preceded by ^ (or followed by
$), is constrained to matches that begin at the left (or end at
the right) end of a line.
10. A regular expression of form 1-9 picks out the longest among the
leftmost matches in a line.
11. An empty regular expression stands for a copy of the last
regular expression encountered.
Regular expressions are used in addresses to specify lines and in one
command (see s below) to specify a portion of a line which is to be
replaced. If it is desired to use one of the regular expression
metacharacters as an ordinary character, that character may be preceded
by `\'. This also applies to the character bounding the regular
expression (often `/') and to `\' itself.
To understand addressing in ed it is necessary to know that at any time
there is a current line. Generally speaking, the current line is the
last line affected by a command; however, the exact effect on the
current line is discussed under the description of the command.
Addresses are constructed as follows.
1. The character `.' addresses the current line.
2. The character `$' 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 name x, which must be a
lower-case letter. Lines are marked with the k command
described below.
5. A regular expression enclosed in slashes `/' addresses the line
found by searching forward from the current line and stopping at
the first line containing a string that matches the regular
expression. If necessary the search wraps around to the
beginning of the buffer.
6. A regular expression enclosed in queries `?' addresses the line
found by searching backward from the current line and stopping
at the first line containing a string that matches 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. 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 (resp.
subtracted). As a consequence of this rule and rule 8, the
address `-' refers to the line before the current line.
Moreover, trailing `+' and `-' characters have cumulative
effect, so `--' refers to the current line less 2.
10. To maintain compatibility with earlier versions of the editor,
the character `^' in addresses is equivalent to `-'.
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, most commands may be suffixed by `p' or by
`l', in which case the current line is either printed or listed
respectively in the way discussed below. Commands may also be suffixed
by `n', meaning the output of the command is to be line numbered.
These suffixes may be combined in any order.
(.)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 line preceding the
deleted lines.
(., .)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. If `filename' is missing, the
remembered name is used.
E filename
This command is the same as e, except that no diagnostic results
when no w has been given since the last buffer alteration.
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,$)g/regular expression/command list
In the global command, the first step is to mark every line which
matches the given regular expression. Then for every such line,
the given command list is executed with `.' initially set to that
line. A single command or the first of multiple commands appears
on the same line with the global command. All lines of a multi-
line list except the last line must be ended with `\'. A, i, and
c commands and associated input are permitted; the `.' terminating
input mode may be omitted if it would be on the last line of the
command list. The commands g and v are not permitted in the
command list.
(.)i
<text>
.
This command inserts the given text before the addressed line.
`.' is left at the last line input, or, if there were none, at the
line before the addressed line. This command differs from the a
command only in the placement of the text.
(., .+1)j
This command joins the addressed lines into a single line;
intermediate newlines simply disappear. `.' is left at the
resulting line.
( . )kx
The mark command marks the addressed line with name x, which must
be a lower-case letter. The address form `′x' then addresses this
line.
(., .)l
The list command prints the addressed lines in an unambiguous way:
non-graphic characters are printed in two-digit octal, and long
lines are folded. The l command may be placed on the same line
after any non-i/o command.
(., .)ma
The move command repositions the addressed lines after the line
addressed by a. The last of the moved lines becomes the current
line.
(., .)p
The print command prints the addressed lines. `.' is left at the
last line printed. The p command may be placed on the same line
after any non-i/o command.
(., .)P
This command is a synonym for p.
q The quit command causes ed to exit. No automatic write of a file
is done.
Q This command is the same as q, except that no diagnostic results
when no w has been given since the last buffer alteration.
($)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 file name is remembered if there
was no remembered file name already. 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 punctuation character 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
string matching the regular expression. The special meaning of
`&' in this context may be suppressed by preceding it by `\'. The
characters `\n' where n is a digit, are replaced by the text
matched by the n-th regular subexpression enclosed between `\('
and `\)'. When nested, parenthesized subexpressions are present,
n is determined by counting occurrences of `\(' starting from the
left.
Lines may be split by substituting new-line characters into them.
The new-line in the replacement string must be escaped by
preceding it by `\'.
One or two trailing delimiters may be omitted, implying the `p'
suffix. The special form `s' followed by no delimiters repeats
the most recent substitute command on the addressed lines. The
`s' may be followed by the letters r (use the most recent regular
expression for the left hand side, instead of the most recent left
hand side of a substitute command), p (complement the setting of
the p suffix from the previous substitution), or g (complement the
setting of the g suffix). These letters may be combined in any
order.
(., .)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).
`.' is left on the last line of the copy.
(., .)u
The undo command restores the buffer to its state before the most
recent buffer modifying command. The current line is also
restored. Buffer modifying commands are a, c, d, g, i, k, m, r,
s, t, and v. For purposes of undo, g and v are considered to be a
single buffer modifying command. Undo is its own inverse.
If ed runs out of memory this full undo is not possible, and u can
only undo the effect of the most recent substitute on the current
line. This restricted undo also applies to editor scripts when ed
is invoked with the - option.
(1, $)v/regular expression/command list
This command is the same as the global command g except that the
command list is executed g 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. The file name is
remembered if there was no remembered file name already. 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 printed.
(1, $)W filename
This command is the same as w, except that the addressed lines are
appended to the file.
x A key string is demanded from the standard input. Later r, e and
w commands will encrypt and decrypt the text with this key by the
algorithm of crypt(1). An explicitly empty key turns off
encryption. (.+1)z or,
(.+1)zn
This command scrolls through the buffer starting at the addressed
line. 22 (or n, if given) lines are printed. The last line
printed becomes the current line. The value n is sticky, in that
it becomes the default for future z commands.
($)= The line number of the addressed line is typed. `.' is unchanged
by this command.
!<shell command>
The remainder of the line after the `!' is sent to sh(1) to be
interpreted as a command. `.' is unchanged.
(.+1,.+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 two addresses are present with no
intervening semicolon, ed prints the range of lines. If they are
separated by a semicolon, the second line is printed.
If an interrupt signal (ASCII DEL) is sent, ed prints `?interrupted'
and returns to its command level.
Some size limitations: 512 characters per line, 256 characters per
global command list, 64 characters per file name, and, on mini
computers, 128K characters in the temporary file. The limit on the
number of lines depends on the amount of core: each line takes 2 words.
When reading a file, ed discards ASCII NUL characters and all
characters after the last newline. It refuses to read files containing
non-ASCII characters.
FILES
/tmp/e*
edhup: work is saved here if terminal hangs up
SEE ALSO
B. W. Kernighan, A Tutorial Introduction to the ED Text Editor
B. W. Kernighan, Advanced editing on UNIX
ex(1), sed(1), crypt(1)DIAGNOSTICS
`?name' for inaccessible file; `?self-explanatory message' for other
errors.
To protect against throwing away valuable work, a q or e command is
considered to be in error, unless a w has occurred since the last
buffer change. A second q or e will be obeyed regardless.
BUGS
The l command mishandles DEL.
The undo command causes marks to be lost on affected lines.
The x command, -x option, and special treatment of hangups only work on
UNIX.
7th Edition April 29, 1985 ED(1)
