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ED(1) UNIX Programmer's Manual ED(1)
NAME
ed - text editor
SYNOPSIS
ed [ - ] [ -x ] [ name ]
DESCRIPTION
_E_d is the standard text editor.
If a _n_a_m_e argument is given, _e_d simulates an _e command (see
below) on the named file; that is to say, the file is read
into _e_d'_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
character counts by _e, _r, and _w commands.
_E_d 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 _b_u_f_f_e_r.
Commands to _e_d have a simple and regular structure: zero or
more _a_d_d_r_e_s_s_e_s followed by a single character _c_o_m_m_a_n_d, pos-
sibly 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 _e_d
is accepting text, it is said to be in _i_n_p_u_t _m_o_d_e. In this
mode, no commands are recognized; all input is merely col-
lected. Input mode is left by typing a period `.' alone at
the beginning of a line.
_E_d supports a limited form of _r_e_g_u_l_a_r _e_x_p_r_e_s_s_i_o_n notation.
A regular expression specifies a set of strings of charac-
ters. A member of this set of strings is said to be _m_a_t_c_h_e_d
by the regular expression. In the following specification
for regular expressions the word `character' means any char-
acter 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 expres-
sion.
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 reg-
ular 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 fol-
lowed by $), is constrained to matches that begin at
the left (or end at the right) end of a line.
10. A regular expression of form 1-9 picks out the longest
among the leftmost matches in a line.
11. An empty regular expression stands for a copy of the
last regular expression encountered.
Regular expressions are used in addresses to specify lines
and in one command (see _s below) to specify a portion of a
line which is to be replaced. If it is desired to use one
of the regular expression metacharacters as an ordinary
character, that character may be preceded by `\'. This also
applies to the character bounding the regular expression
(often `/') and to `\' itself.
To understand addressing in _e_d it is necessary to know that
at any time there is a _c_u_r_r_e_n_t _l_i_n_e. Generally speaking, the
current line is the last line affected by a command; how-
ever, the exact effect on the current line is discussed
under the description of the command. Addresses are con-
structed as follows.
1. The character `.' addresses the current line.
2. The character `$' 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 `-' charac-
ters 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 for-
ward and backward searches (`/', `?'). The second address
of any two-address sequence must correspond to a line fol-
lowing the line corresponding to the first address.
In the following list of _e_d 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 com-
mand 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.
(.)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 diagnos-
tic 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,$)g/regular expression/command list
In the global command, the first step is to mark every
line which matches the given regular expression. Then
for every such line, the given command list is executed
with `.' initially set to that line. A single command
or the first of multiple commands appears on the same
line with the global command. All lines of a multi-
line list except the last line must be ended with `\'.
_A, _i, and _c commands and associated input are permit-
ted; the `.' terminating input mode may be omitted if
it would be on the last line of the command list. The
commands _g and _v are not permitted in the command list.
(.)i
<text>
.
This command inserts the given text before the
addressed line. `.' is left at the last line input,
or, if there were none, at the line before the
addressed line. This command differs from the _a com-
mand only in the placement of the text.
(., .+1)j
This command joins the addressed lines into a single
line; intermediate newlines simply disappear. `.' is
left at the resulting line.
( . )k_x
The mark command marks the addressed line with name _x,
which must be a lower-case letter. The address form
`'_x' then addresses this line.
(., .)l
The list command prints the addressed lines in an unam-
biguous way: non-graphic characters are printed in
two-digit octal, and long lines are folded. The _l com-
mand may be placed on the same line after any non-i/o
command.
(., .)m_a
The move command repositions the addressed lines after
the line addressed by _a. The last of the moved lines
becomes the current line.
(., .)p
The print command prints the addressed lines. `.' is
left at the last line printed. The _p command may be
placed on the same line after any non-i/o command.
(., .)P
This command is a synonym for _p.
q The quit command causes _e_d to exit. No automatic write
of a file is done.
Q This command is the same as _q, except that no diagnos-
tic results when no _w has been given since the last
buffer alteration.
($)r filename
The read command reads in the given file after the
addressed line. If no file name is given, the remem-
bered file name, if any, is used (see _e and _f com-
mands). 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 character other than space or
new-line may be used instead of `/' to delimit the reg-
ular 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 `\'.
(., .)t_a
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 preceding contents of the
current line, which must be the last line in which a
substitution was made.
(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 _e_x_c_e_p_t those matching the regular
expression.
(1, $)w filename
The write command writes the addressed lines onto the
given file. If the file does not exist, it is created
mode 666 (readable and writable by everyone). The file
name is remembered if there was no remembered file name
already. If no file name is given, the remembered file
name, if any, is used (see _e and _f commands). `.' is
unchanged. If the command is successful, the number of
characters written is printed.
(1,$)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 _c_r_y_p_t(1). An
explicitly empty key turns off encryption.
($)= 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
_s_h(1) to be interpreted as a command. `.' is
unchanged.
(.+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 an interrupt signal (ASCII DEL) is sent, _e_d prints a `?'
and returns to its command level.
Some size limitations: 512 characters per line, 256 charac-
ters per global command list, 64 characters per file name,
and 128K characters in the temporary file. The limit on the
number of lines depends on the amount of core: each line
takes 1 word.
When reading a file, _e_d discards ASCII NUL characters and
all characters after the last newline. It refuses to read
files containing non-ASCII characters.
FILES
/tmp/e*
ed.hup: work is saved here if terminal hangs up
SEE ALSO
B. W. Kernighan, _A _T_u_t_o_r_i_a_l _I_n_t_r_o_d_u_c_t_i_o_n _t_o _t_h_e _E_D _T_e_x_t _E_d_i_-
_t_o_r
B. W. Kernighan, _A_d_v_a_n_c_e_d _e_d_i_t_i_n_g _o_n _U_N_I_X
sed(1), crypt(1)
DIAGNOSTICS
`?name' for inaccessible file; `?' for errors in commands;
`?TMP' for temporary file overflow.
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.
A ! command cannot be subject to a _g command.
Because 0 is an illegal address for a _w command, it is not
possible to create an empty file with _e_d.
