ed
- text editor
ed
[-] [-sx] [-p string] [file]
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, fol-
lowed 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.
OPTIONS -s Suppresses diagnostics. This should be used if ed's standard input is from a script.
-x Prompts for an encryption key to be used in subsequent reads
and writes (see the x
command).
-p string
Specifies a command prompt. This may be toggled on and off
with the P
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
LINE ADDRESSING
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 (i.e., +, - 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.
. |
g/string/
globally searches and outputs all lines containing string.
s
command for selecting old text to be replaced with new.
Regular expressions can represent classes of strings.
The left most longest match is selected if several strings match.
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 locale(5) (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.
^
If ^
is the first character of a regular expression, 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)
\(n\)
Defines a subexpression n
.
A subsequent backreference of the form \n
expands to the text matched by the n
th,
n
is a number in the range 1,9
For example, the regular expression `\(.*\)\1'
matches any string consisting of identical adjacent substrings.
Subexpressions are ordered relative to their left delimiter.
Subexpressions may be nested.
* Matches the single character regular expression or subexpression immediately preceding it zero or more times.
If *
is the first character of a regular expression or subexpression, then it matches itself.
The *
operator sometimes yields unexpected results. 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 left-most
match.
\{n,m\} or \{n,\} or \{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
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 com- mand 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 parenthesis).
(.)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) commandlist.
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 for 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 by with 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 the !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 to be 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 the
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,$)v/pat/command-list
Applies command-list to each of the addressed lines not matching a regular expression re. This is similar to the g
command.
(1,$)V/re/
Interactively edits the addressed lines not matching a regular
expression re. This is similar to the G
command.
(1,$)w file Writes the addressed lines to file. Any previous contents of file is lost without warning. If there is no default filename, then the default filename is set to file, otherwise it is unchanged. If no filename is specified, then the default filename is used. The current address is unchanged.
(1,$)wq file
Writes the addressed lines to file, and then executes a q
command.
(1,$)w !command Writes the addressed lines to the standard input of `!command', (see the !command below). The default filename and current address are unchanged.
(1,$)W file
Appends the addressed lines to the end of file. This is similar to the w
command, expect that the previous contents of
file is 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.
!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.
($)= Prints the line number of the addressed line.
(.+1)newline Prints the addressed line, and sets the current address to that line.
FILES
/tmp/ed.* Buffer file
ed.hup The file to whiched
attempts to write the buffer
if the terminal hangs up.
SEE ALSO vi(1), sed(1), regex(3), bdes(1), sh(1).
USD:12-13
B. W. Kernighan and P. J. Plauger, Software Tools in Pascal , Addison- Wesley, 1981.
LIMITATIONS
ed
processes file arguments for backslash escapes, i.e., in a file-
name, any characters preceded by a backslash (\) are interpreted liter-
ally.
If a text (non-binary) file is not terminated by a newline character,
thened
appends one on reading/writing it. In the case of a binary
file,ed
does not append a newline on reading/writing.
per line overhead: 4 ints
DIAGNOSTICS
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 quited
or edit another
file before writing a modified buffer results in an error. If the com-
mand is entered a second time, it succeeds, but any changes to the
buffer are lost.
21 May 1993 ED(1) lines 505-535/535 (END)