ed - text editor
ed [-] [-sx] [-p string] [file]
ed is a line-oriented text editor. It is used to create,
display, modify,
and otherwise manipulate text files. If invoked with a
file argument,
then a copy of file is read into the editor's buffer.
Changes are
made to this copy and not directly to file itself. Upon
quitting ed, any
changes not explicitly saved with a w command are lost.
Editing is done in two distinct modes: command and input.
When first invoked,
ed is in command mode. In this mode, commands are
read from the
standard input and executed to manipulate the contents of
the editor
buffer.
A typical command might look like:
,s/old/new/g
which replaces all occurrences of the string "old" with
"new".
When an input command, such as a (append), i (insert), or c
(change) is
given, ed enters input mode. This is the primary means of
adding text to
a file. In this mode, no commands are available; instead,
the standard
input is written directly to the editor buffer. Lines consist of text up
to and including a newline character. Input mode is terminated by entering
a single period (`.') on a line.
All ed commands operate on whole lines or ranges of lines;
e.g., the d
command deletes lines; the m command moves lines, and so on.
It is possible
to modify only a portion of a line by means of replacement, as in
the example above. However, even here, the s command is applied to whole
lines at a time.
In general, ed commands consist of zero or more line addresses, followed
by a single character command and possibly additional parameters; i.e.,
commands have the structure:
[address [,address]]command[parameters]
The address(es) indicate the line or range of lines to be
affected by the
command. If fewer addresses are given than the command accepts, then default
addresses are supplied.
The options are as follows:
- Same as the -s option (deprecated).
-p string Specifies a command prompt. This may be toggled
on and off
with the P command.
-s Suppress diagnostics. This should be used if ed
standard input
is from a script.
-x Prompt for an encryption key to be used in subsequent reads
and writes (see the x command).
file Specifies the name of a file to read. If file is
prefixed
with a bang (`!'), then it is interpreted as a
shell command.
In this case, what is read is the standard output
of file executed
via sh(1). To read a file whose name begins with a
bang, prefix the name with a backslash (`'). The
default
filename is set to file only if it is not prefixed with a
bang.
LINE ADDRESSING [Toc] [Back]
An address represents the number of a line in the buffer.
ed maintains a
current address which is typically supplied to commands as
the default
address when none is specified. When a file is first read,
the current
address is set to the last line of the file. In general,
the current address
is set to the last line affected by a command.
A line address is constructed from one of the bases in the
list below,
optionally followed by a numeric offset. The offset may include any combination
of digits, operators (e.g., `+', `-', and `^'), and
whitespace.
Addresses are read from left to right, and their values are
computed relative
to the current address.
One exception to the rule that addresses represent line numbers is the
address 0 (zero). This means ``before the first line'', and
is legal
wherever it makes sense.
An address range is two addresses separated either by a comma or semicolon.
The value of the first address in a range cannot exceed the value
of the second. If only one address is given in a range,
then the second
address is set to the given address. If an n-tuple of addresses is given
where n > 2, then the corresponding range is determined by
the last two
addresses in the n-tuple. If only one address is expected,
then the last
address is used.
Each address in a comma-delimited range is interpreted relative to the
current address. In a semi-colon-delimited range, the first
address is
used to set the current address, and the second address is
interpreted
relative to the first.
The following address symbols are recognized:
. The current line (address) in the buffer.
$ The last line in the buffer.
n The nth line in the buffer, where n is a number in
the range
[0,$].
- or ^ The previous line. This is equivalent to -1 and may
be repeated
with cumulative effect.
-n or ^n
The nth previous line, where n is a non-negative
number.
+ The next line. This is equivalent to +1 and may be
repeated with
cumulative effect.
+n The nth next line, where n is a non-negative number.
, or % The first through last lines in the buffer. This is
equivalent
to the address range 1,$.
; The current through last lines in the buffer. This
is equivalent
to the address range .,$.
/re/ The next line containing the regular expression re.
The search
wraps to the beginning of the buffer and continues
down to the
current line, if necessary. "//" repeats the last
search.
?re? The previous line containing the regular expression
re. The
search wraps to the end of the buffer and continues
up to the
current line, if necessary. "??" repeats the last
search.
'lc The line previously marked by a k (mark) command,
where lc is a
lower case letter.
REGULAR EXPRESSIONS [Toc] [Back]
Regular expressions are patterns used in selecting text.
For example,
the ed command
g/string/
prints all lines containing "string". Regular expressions
are also used
by the s command for selecting old text to be replaced with
new.
In addition to specifying string literals, regular expressions can represent
classes of strings. Strings thus represented are said
to be matched
by the corresponding regular expression. If it is possible
for a regular
expression to match several strings in a line, then the
leftmost longest
match is the one selected.
The following symbols are used in constructing regular expressions:
c Any character c not listed below, including `{',
`}', `(', `)',
`<', and `>' matches itself.
c Any backslash-escaped character c, except for `{',
`}', `(',
`)', `<', and `>' matches itself.
. Matches any single character.
[char-class]
Matches any single character in char-class. To
include a `]'
in char-class, it must be the first character. A
range of
characters may be specified by separating the end
characters of
the range with a `-'; e.g., a-z specifies the lower case characters.
The following literal expressions can also be used in
char-class to specify sets of characters:
[:alnum:] [:cntrl:] [:lower:] [:space:]
[:alpha:] [:digit:] [:print:] [:upper:]
[:blank:] [:graph:] [:punct:] [:xdigit:]
If `-' appears as the first or last character of
char-class,
then it matches itself. All other characters in
char-class
match themselves.
Patterns in char-class of the form [.col-elm.] or
[=col-elm=]
where col-elm is a collating element are interpreted according
to setlocale(3) (not currently supported). See
regex(3) for an
explanation of these constructs.
[^char-class]
Matches any single character, other than newline,
not in char-
class. char-class is defined as above.
^ If `^' is the first character of a regular expression, then it
anchors the regular expression to the beginning of
a line.
Otherwise, it matches itself.
$ If `$' is the last character of a regular expression, it anchors
the regular expression to the end of a line.
Otherwise,
it matches itself.
< Anchors the single character regular expression or
subexpression
immediately following it to the beginning of
a word.
(This may not be available.)
> Anchors the single character regular expression or
subexpression
immediately following it to the end of a
word. (This may
not be available.)
re Defines a subexpression re. Subexpressions may be
nested. A
subsequent backreference of the form n, where n is
a number in
the range [1,9], expands to the text matched by
the nth subexpression.
For example, the regular expression
_.*__b*
matches the beginning of the string "abbb" (as opposed to the
substring "bbb"), since a null match is the only
leftmost
match.
n,m n, n
Matches the single character regular expression or
subexpression
immediately preceding it at least n and at
most m times.
If m is omitted, then it matches at least n times.
If the comma
is also omitted, then it matches exactly n
times.
Additional regular expression operators may be defined depending on the
particular regex(3) implementation.
COMMANDS [Toc] [Back]
All ed commands are single characters, though some require
additional parameters.
If a command's parameters extend over several
lines, then each
line except for the last must be terminated with a backslash
(`').
In general, at most one command is allowed per line. However, most commands
accept a print suffix, which is any of p (print), l
(list), or n
(enumerate), to print the last line affected by the command.
An interrupt (typically ^C) has the effect of aborting the
current command
and returning the editor to command mode.
ed recognizes the following commands. The commands are
shown together
with the default address or address range supplied if none
is specified
(in parentheses), and other possible arguments on the right.
(.)a Appends text to the buffer after the addressed line.
Text is entered
in input mode. The current address is set to
last line entered.
(.,.)c
Changes lines in the buffer. The addressed lines are
deleted from
the buffer, and text is appended in their place. Text
is entered
in input mode. The current address is set to last
line entered.
(.,.)d
Deletes the addressed lines from the buffer. If there
is a line
after the deleted range, then the current address is
set to this
line. Otherwise the current address is set to the
line before the
deleted range.
e file
Edits file, and sets the default filename. If file is
not specified,
then the default filename is used. Any lines in
the buffer
are deleted before the new file is read. The current
address is
set to the last line read.
e !command
Edits the standard output of !command, (see !command
below). The
default filename is unchanged. Any lines in the
buffer are deleted
before the output of command is read. The current address is set
to the last line read.
E file
Edits file unconditionally. This is similar to the e
command, except
that unwritten changes are discarded without
warning. The
current address is set to the last line read.
f file
Sets the default filename to file. If file is not
specified, then
the default unescaped filename is printed.
(1,$)g/re/command-list
Applies command-list to each of the addressed lines
matching a regular
expression re. The current address is set to the
line currently
matched before command-list is executed. At
the end of the
g command, the current address is set to the last line
affected by
command-list.
Each command in command-list must be on a separate
line, and every
line except for the last must be terminated by a backslash (`').
Any commands are allowed, except for g, G, v, and V.
A newline
alone in command-list is equivalent to a p command.
(1,$)G/re/
Interactively edits the addressed lines matching a
regular expression
re. For each matching line, the line is printed,
the current
address is set, and the user is prompted to enter a
command-list.
At the end of the G command, the current address is
set to the last
line affected by (the last) command-list.
The format of command-list is the same as that of the
g command. A
newline alone acts as a null command list. A single
`&' repeats
the last non-null command list.
H Toggles the printing of error explanations. By default, explanations
are not printed. It is recommended that ed
scripts begin
with this command to aid in debugging.
h Prints an explanation of the last error.
(.)i Inserts text in the buffer before the current line.
Text is entered
in input mode. The current address is set to
the last line
entered.
(.,.+1)j
Joins the addressed lines. The addressed lines are
deleted from
the buffer and replaced by a single line containing
their joined
text. The current address is set to the resultant
line.
(.)klc
Marks a line with a lower case letter lc. The line
can then be addressed
as 'lc (i.e., a single quote followed by lc)
in subsequent
commands. The mark is not cleared until the line is
deleted or
otherwise modified.
(.,.)l
Prints the addressed lines unambiguously. If a single
line fills
more than one screen (as might be the case when viewing a binary
file, for instance), a ``--More--'' prompt is printed
on the last
line. ed waits until the RETURN key is pressed before
displaying
the next screen. The current address is set to the
last line
printed.
(.,.)m(.)
Moves lines in the buffer. The addressed lines are
moved to after
the right-hand destination address, which may be the
address 0
(zero). The current address is set to the last line
moved.
(.,.)n
Prints the addressed lines along with their line numbers. The current
address is set to the last line printed.
(.,.)p
Prints the addressed lines. The current address is
set to the last
line printed.
P Toggles the command prompt on and off. Unless a
prompt was specified
with the command-line option -p string, the command prompt is
by default turned off.
q Quits ed.
Q Quits ed unconditionally. This is similar to the q
command, except
that unwritten changes are discarded without warning.
($)r file
Reads file to after the addressed line. If file is
not specified,
then the default filename is used. If there was no
default filename
prior to the command, then the default filename
is set to
file. Otherwise, the default filename is unchanged.
The current
address is set to the last line read.
($)r !command
Reads to after the addressed line the standard output
of !command,
(see !command below). The default filename is unchanged. The current
address is set to the last line read.
(.,.)s/re/replacement/ (.,.)s/re/replacement/g
(.,.)s/re/replacement/n
Replaces text in the addressed lines matching a regular expression
re with replacement. By default, only the first match
in each line
is replaced. If the g (global) suffix is given, then
every match
is replaced. The n suffix, where n is a positive number, causes
only the nth match to be replaced. It is an error if
no substitutions
are performed on any of the addressed lines.
The current address
is set the last line affected.
re and replacement may be delimited by any character
other than
space and newline (see the s command below). If one
or two of the
last delimiters is omitted, then the last line affected is printed
as though the print suffix p were specified.
An unescaped `&' in replacement is replaced by the
currently
matched text. The character sequence m, where m is a
number in
the range [1,9], is replaced by the mth backreference
expression of
the matched text. If replacement consists of a single
`%', then
replacement from the last substitution is used. Newlines may be
embedded in replacement if they are escaped with a
backslash (`').
(.,.)s
Repeats the last substitution. This form of the s
command accepts
a count suffix n, or any combination of the characters
r, g, and p.
If a count suffix n is given, then only the nth match
is replaced.
The r suffix causes the regular expression of the last
search to be
used instead of that of the last substitution. The g
suffix toggles
the global suffix of the last substitution. The
p suffix toggles
the print suffix of the last substitution. The
current address
is set to the last line affected.
(.,.)t(.)
Copies (i.e., transfers) the addressed lines to after
the righthand
destination address, which may be the address 0
(zero). The
current address is set to the last line copied.
u Undoes the last command and restores the current address to what it
was before the command. The global commands g, G, v,
and V are
treated as a single command by undo. u is its own inverse.
(1,$)v/re/command-list
Applies command-list to each of the addressed lines
not matching a
regular expression re. This is similar to the g command.
(1,$)V/re/
Interactively edits the addressed lines not matching a
regular expression
re. This is similar to the G command.
(1,$)w file
Writes the addressed lines to file. Any previous contents of file
are lost without warning. If there is no default
filename, then
the default filename is set to file, otherwise it is
unchanged. If
no filename is specified, then the default filename is
used. The
current address is unchanged.
(1,$)wq file
Writes the addressed lines to file, and then executes
a q command.
(1,$)w !command
Writes the addressed lines to the standard input of
!command, (see
!command below). The default filename and current address are unchanged.
(1,$)W file
Appends the addressed lines to the end of file. This
is similar to
the w command, except that the previous contents of
file are not
clobbered. The current address is unchanged.
x Prompts for an encryption key which is used in subsequent reads and
writes. If a newline alone is entered as the key,
then encryption
is turned off. Otherwise, echoing is disabled while a
key is read.
Encryption/decryption is done using the bdes(1) algorithm.
(.+1)zn
Scrolls n lines at a time starting at addressed line.
If n is not
specified, then the current window size is used. The
current address
is set to the last line printed.
($)= Prints the line number of the addressed line.
(.+1)newline
Prints the addressed line, and sets the current address to that
line.
!command
Executes command via sh(1). If the first character of
command is
`!', then it is replaced by text of the previous
!command. ed does
not process command for `' (backslash) escapes. However, an unescaped
`%' is replaced by the default filename. When
the shell
returns from execution, a `!' is printed to the standard output.
The current line is unchanged.
ed processes file arguments for backslash escapes, i.e., in
a filename,
any characters preceded by a backslash (`') are interpreted
literally.
If a text (non-binary) file is not terminated by a newline
character,
then ed appends one on reading/writing it. In the case of a
binary file,
ed does not append a newline on reading/writing.
/tmp/ed.* buffer file
ed.hup where ed attempts to write the buffer if the terminal hangs up
When an error occurs, ed prints a `?' and either returns to
command mode
or exits if its input is from a script. An explanation of
the last error
can be printed with the h (help) command.
Since the g (global) command masks any errors from failed
searches and
substitutions, it can be used to perform conditional operations in
scripts; e.g.,
g/old/s//new/
replaces any occurrences of "old" with "new".
If the u (undo) command occurs in a global command list,
then the command
list is executed only once.
If diagnostics are not disabled, attempting to quit ed or
edit another
file before writing a modified buffer results in an error.
If the command
is entered a second time, it succeeds, but any changes
to the buffer
are lost.
bdes(1), sed(1), sh(1), vi(1), regex(3)
"A Tutorial Introduction to the UNIX Text Editor",
/usr/share/doc/usd/09.edtut/.
"Advanced Editing on UNIX", /usr/share/doc/usd/10.edadv/.
B. W. Kernighan and P. J. Plauger, Software Tools in Pascal,
1981,
Addison-Wesley.
An ed command appeared in Version 1 AT&T UNIX.
OpenBSD 3.6 May 2, 1993
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