ed, red -- text editor
ed [-] [-sx] [-p string] [file]
red [-] [-sx] [-p string] [file]
The ed utility is a line-oriented text editor. It is used to create,
display, modify and otherwise manipulate text files. When invoked as
red, the editor runs in "restricted" mode, in which the only difference
is that the editor restricts the use of filenames which start with `!'
(interpreted as shell commands by ed) or contain a `/'. Note that editing
outside of the current directory is only prohibited if the user does
not have write access to the current directory. If a user has write
access to the current directory, then symbolic links can be created in
the current directory, in which case red will not stop the user from
editing the file that the symbolic link points to.
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 following options are available:
-s Suppress diagnostics. This should be used if ed's standard input
is from a script.
-x Prompt for an encryption key to be used in subsequent reads and
writes (see the x command).
-p string
Specify a command prompt. This may be toggled on and off with
the P command.
file Specify 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. The ed utility
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 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 are patterns used in selecting text. For example,
the 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 a 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 left-most
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.
. Match any single character.
[char-class]
Match 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
the current locale settings (not currently supported). See
regex(3) and re_format(7) for an explanation of these constructs.
[^char-class]
Match 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.
\< Anchor the single character regular expression or subexpression
immediately following it to the beginning of a word. (This may
not be available)
\> Anchor the single character regular expression or subexpression
immediately following it to the end of a word. (This may not be
available)
\(re\) Define 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 `\(.*\)\1' matches any
string consisting of identical adjacent substrings. Subexpressions
are ordered relative to their left delimiter.
* Match 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\}
Match 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.
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.
The ed utility recognizes the following commands. The commands are shown
together with the default address or address range supplied if none is
specified (in parenthesis).
(.)a Append text to the buffer after the addressed line. Text is
entered in input mode. The current address is set to last line
entered.
(.,.)c Change 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 Delete 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 Edit 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
Edit 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 Edit 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 Set the default filename to file. If file is not specified, then
the default unescaped filename is printed.
(1,$)g/re/command-list
Apply 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 edit 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 Toggle 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 Print an explanation of the last error.
(.)i Insert 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
Join 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 Mark 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 Print 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. The ed utility waits until the RETURN key is pressed
before displaying the next screen. The current address is set to
the last line printed.
(.,.)m(.)
Move 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 Print the addressed lines along with their line numbers. The
current address is set to the last line printed.
(.,.)p Print the addressed lines. The current address is set to the
last line printed.
P Toggle 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 Quit ed.
Q Quit ed unconditionally. This is similar to the q command,
except that unwritten changes are discarded without warning.
($)r file
Read 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
Read 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
Replace 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 m th 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 Repeat 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(.)
Copy (i.e., transfer) 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 Undo 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,$)v/re/command-list
Apply command-list to each of the addressed lines not matching a
regular expression re. This is similar to the g command.
(1,$)V/re/
Interactively edit the addressed lines not matching a regular
expression re. This is similar to the G command.
(1,$)w file
Write the addressed lines to file. Any previous contents of file
is lost without warning. If there is no default filename, then
the default filename is set to file, otherwise it is unchanged.
If no filename is specified, then the default filename is used.
The current address is unchanged.
(1,$)wq file
Write the addressed lines to file, and then executes a q command.
(1,$)w !command
Write the addressed lines to the standard input of !command, (see
the !command below). The default filename and current address
are unchanged.
(1,$)W file
Append 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 Prompt 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
Scroll 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
Execute command via sh(1). If the first character of command is
`!', then it is replaced by text of the previous !command. The
ed utility 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.
($)= Print the line number of the addressed line.
(.+1)newline
Print the addressed line, and sets the current address to that
line.
/tmp/ed.* buffer file
ed.hup the file to which ed attempts to write the buffer if the terminal
hangs up
bdes(1), sed(1), sh(1), vi(1), regex(3)
USD:12-13
B. W. Kernighan and P. J. Plauger, Software Tools in Pascal, 1981,
Addison-Wesley.
The ed utility 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.
per line overhead: 4 ints
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.
An ed command appeared in Version 1 AT&T UNIX.
FreeBSD 5.2.1 May 21, 1993 FreeBSD 5.2.1 [ Back ] |
