ed —
text editor
ed |
[ -
]
[-s
]
[-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.
Many
ed commands and line addresses support
basic regular expressions (BREs). See
re_format(7) for more
information on regular expressions.
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.
-
-
- 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.
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 semi-colon. 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.
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.
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. If no lines were matched, the
current line number remains unchanged.
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. If no lines were
matched, the current line number remains unchanged.
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. 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 right-hand
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,$)
W
file
- Appends the addressed lines to the end of
file. This is similar to the
w command, except that the previous
contents of file are not clobbered. The current address is unchanged.
-
-
- (.+1)
zn
- Scrolls n lines at a time starting at
addressed line. If n is not specified,
then the current window size is used. The current address is set to the
last line printed.
-
-
- ($)
=
- 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.
-
-
SIGHUP- If the current buffer has changed since it was last written,
ed attempts to write the buffer to the
file ed.hup. Nothing is written to the
currently remembered file, and ed
exits.
-
-
SIGINT- When an interrupt occurs,
ed prints
‘?\n’ and returns to command mode. If interrupted during
text input, the text already input is written to the current buffer, as if
text input had been normally terminated.
-
-
SIGQUIT- This signal is ignored.
-
-
SIGWINCH- The screen is resized.
- /tmp/ed.*
- buffer file
- ed.hup
- where
ed attempts to write the buffer
if the terminal hangs up
The
ed utility exits 0 on success,
and >0 if an error occurs.
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.
sed(1),
sh(1),
vi(1),
re_format(7)
B. W. Kernighan and
P. J. Plauger, Software Tools in
Pascal, 1981,
Addison-Wesley.
The
ed utility is compliant with the
IEEE Std 1003.1-2008
(“POSIX.1”) specification.
The commands
s (to repeat the last
substitution),
W,
wq, and
z as well as the address specifier
‘%’ are extensions to that specification.
The
IEEE Std 1003.1-2008
(“POSIX.1”) specification says the ‘^’
address specifier is neither required nor prohibited; additionally, it says
behaviour for the
- option is
“unspecified”.
An
ed command appeared in
Version 1 AT&T UNIX.
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.
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