ED(1) GENIX Programmer's Manual ED(1)
NAME
ed - text editor
SYNOPSIS
ed [ - ] [ -p[prompt] ] [ -u ] [ -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 -p is present, ed prompts for commands
with `* ' (or prompt if given.) If -u is present, all lower case
text in the buffer is converted to upper case. 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 regu-
lar expression specifies a set of strings of characters. A member
of this set of strings is said to be matched by the regular expres-
sion. In the following specification for regular expressions the
word `character' means any character but newline.
1. Any character except a special character matches itself. Spe-
cial 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 charac-
ter 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
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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
$), is constrained to matches that begin at the left (or end at
the right) end of a line.
10. A regular expression of form 1-9 picks out the longest among
the leftmost matches in a line.
11. An empty regular expression stands for a copy of the last regu-
lar expression encountered.
Regular expressions are used in addresses to specify lines and in
one command (see s below) to specify a portion of a line which is to
be replaced. If it is desired to use one of the regular expression
metacharacters as an ordinary character, that character may be pre-
ceded by `\'. This also applies to the character bounding the regu-
lar expression (often `/') and to `\' itself.
To understand addressing in ed it is necessary to know that at any
time there is a current line. Generally speaking, the current line
is the last line affected by a command; however, the exact effect on
the current line is discussed under the description of the command.
Addresses are constructed as follows.
1. The character `.' addresses the current line.
2. The character `$' 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
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at the first line containing a string that matches the regular
expression. If necessary the search wraps around to the begin-
ning 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 `-' fol-
lowed 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 subtrac-
tion 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. sub-
tracted). As a consequence of this rule and rule 8, the
address `-' refers to the line before the current line. More-
over, 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. The special
form `%' is an abbreviation for the address pair `1,$'.
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
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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 preced-
ing 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 altera-
tion.
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 `.' ini-
tially set to that line. A single command or the first of mul-
tiple commands appears on the same line with the global com-
mand. All lines of a multi-line list except the last line must
be ended with `\'. A, i, and c commands and associated input
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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.
(., .)n
The number command prints the addressed lines with line numbers
and a tab at the left.
(., .)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 altera-
tion.
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($)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 remem-
bered if there was no remembered file name already. Address
`0' is legal for r and causes the file to be read at the begin-
ning 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 mean-
ing 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 subexpres-
sions 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 regu-
lar 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
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The undo command restores the buffer to it's state before the
most recent buffer modifying command. The current line is also
restored. Buffer modifying commands are a, c, d, g, i, k, and
v. For purposes of undo, g and v are considered to be a single
buffer modifying command. Undo is its own inverse.
When ed runs out of memory (at about 8000 lines on any 16 bit
mini-computer such as the PDP-11) This full undo is not possi-
ble, and u can only undo the effect of the most recent substi-
tute 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.
(1, $)wq filename
This command is the same as w except that afterwards a q com-
mand is done, exiting the editor after the file is written.
x A key string is demanded from the standard input. Later r, e
and w commands will encrypt and decrypt the text with this key
by the algorithm of crypt(1). An explicitly empty key turns
off encryption. (.+1)z or,
(.+1)zn
This command scrolls through the buffer starting at the
addressed line. 22 (or n, if given) lines are printed. The
last line printed becomes the current line. The value n is
sticky, in that it becomes the default for future z commands.
($)= 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>
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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 com-
puters, 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 char-
acters 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
sed(1), crypt(1)
DIAGNOSTICS
`?name' for inaccessible file; `?self-explanitory 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.
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