ed.html

unix 下的C开发手册,还用详细的例程。

If an end-of-file is detected on standard input when a command
is expected, the
<i>ed</i>
utility acts as if a
<b>q</b>
command had been entered.
<p>
If the closing delimiter of an RE or of a
replacement string (for example,
<b>/</b>)
in a
<b>g</b>,
<b>G</b>,
<b>s</b>,
<b>v</b>
or
<b>V</b>
command would be the last character before a newline character,
that delimiter can be omitted, in
which case the addressed line is written.
For example,
the following pairs of commands are equivalent:
<p><code>
<dl compact>

<dt>s/s1/s2<dd>s/s1/s2/p

<dt>g/s1<dd>g/s1/p

<dt>?s1<dd>?s1?

</dl>
</code>
<p>
If an invalid command is entered,
<i>ed</i>
will write the string:
<pre>
<code>
"?\n"
</code>
</pre>
(followed by an explanatory message if
<i>help mode</i>
has been enabled via the
<b>H</b>
command) to standard output and
will continue in command mode with the current line number unchanged.
<h5><a name = "tag_001_014_541_004">&nbsp;</a>Append Command</h5>
<pre>
<code>
<i>Synopsis</i>:	(.)a
	&lt;<i>text</i>&gt;
	.
</code>
</pre>
<p>
The
<b>a</b>
command reads the given text
and appends it after the addressed line;
the current line number will become
the address of the last inserted line or, if there
were none, the addressed line.
Address 0 is valid for this command;
it causes the appended text to be placed
at the beginning of the buffer.
<h5><a name = "tag_001_014_541_005">&nbsp;</a>Change Command</h5>
<pre>
<code>
<i>Synopsis</i>:	(.,.)c
	&lt;<i>text</i>&gt;
	.
</code>
</pre>
<p>
The
<b>c</b>
command deletes the addressed lines, then accepts input
text that replaces these lines;
the current line will be
set to the address of the last line input; or, if there were none,
at the line after the last line deleted;
if the lines deleted were originally at the end of the buffer,
the current line
number will be set to the address of the new last line; if no lines remain
in the buffer, the current line number will be set to zero.
<h5><a name = "tag_001_014_541_006">&nbsp;</a>Delete Command</h5>
<pre>
<code>
<i>Synopsis</i>:	(.,.)d
</code>
</pre>
<p>
The
<b>d</b>
command deletes the addressed lines from the buffer.
The address of the line after the last line deleted will become
the current line number;
if the lines deleted were originally at the end of the buffer,
the current line
number will be set to the address of the new last line; if no lines remain
in the buffer, the current line number will be set to zero.
<h5><a name = "tag_001_014_541_007">&nbsp;</a>Edit Command</h5>
<pre>
<code>
<i>Synopsis</i>:	e <b>[</b><i>file</i><b>]
</b></code>
</pre>
<p>
The
<b>e</b>
command deletes the entire contents of the buffer
and then reads in the file named by the pathname
<i>file</i>.
The current line
number will be set to the address of the last line of the buffer.
If no pathname is given, the currently remembered pathname,
if any, will be used
(see the
<b>f</b>
command).
The number of bytes read will be written to standard output, unless the
<b>-s</b>
option was specified,
in the following format:
<p><code>
<tt>"%d\n"</tt>, &lt;<i>number&nbsp;of&nbsp;bytes&nbsp;read</i>&gt;
</code>
<p>
The name <i>file</i>
will be remembered for possible use as a default pathname
in subsequent
<b>e</b>,
<b>E</b>,
<b>r</b>
and
<b>w</b>
commands.
If
<i>file</i>
is replaced by
<b>!</b>,
the rest of the line
will be taken to be a
shell command line whose output is to be read.
Such a shell command line is not remembered as the current
<i>file</i>.
All marks will be discarded upon the completion of a successful
<b>e</b>
command.
If the buffer has changed since the last time the entire buffer
was written, the user will be warned, as described previously.
<h5><a name = "tag_001_014_541_008">&nbsp;</a>Edit Without Checking Command</h5>
<pre>
<code>
<i>Synopsis</i>:	E <b>[</b><i>file</i><b>]
</b></code>
</pre>
<p>
The
<b>E</b>
command possesses all properties and restrictions of the
<b>e</b>
command except that the editor will not check to see
if any changes have been made to the buffer since the last
w
command.
<h5><a name = "tag_001_014_541_009">&nbsp;</a>Filename Command</h5>
<pre>
<code>
<i>Synopsis</i>:	f <b>[</b><i>file</i><b>]
</b></code>
</pre>
<p>
If
<i>file</i>
is given, the
<b>f</b>
command will change the currently remembered pathname to
<i>file</i>;
whether the name is changed or not,
it then will write the (possibly new) currently remembered pathname
to the standard output
in the following format:
<p><code>
<tt>"%s\n"</tt>, &lt;<i>pathname</i>&gt;
</code>
<p>
The current line number is unchanged.
<h5><a name = "tag_001_014_541_010">&nbsp;</a>Global Command</h5>
<pre>
<code>
<i>Synopsis</i>:	(1,$)g/<i>RE</i>/<i>command list</i>
</code>
</pre>
<p>
In the
<b>g</b>
command, the first step is to mark every line that matches
the given
<i>RE.</i>
Then, for every such line, the given
<i>command list</i> will be executed with
the current line number set to the address of that line.
When the
<b>g</b>
command completes, the current line number will have
the value assigned by the last command in the command list.
If there were no matching lines, the current line number will not be changed.
A single command or the first of a list of commands
will appear on the same line as the global command.
All lines of a multi-line list except the last line will be ended with a
backslash; the
<b>a</b>,
<b>i</b>
and
<b>c</b>
commands and associated input are permitted.
The
.
terminating input mode can be omitted if it would be the
last line of the <i>command list</i>.
An empty <i>command list</i> is equivalent to the
<b>p</b>
command.
The use of the
<b>g</b>,
<b>G</b>,
<b>v</b>,
<b>V</b>
and
<b>!</b>
commands in the
<i>command list</i>
produces undefined results.
Any character other than
space or newline can be used instead of a slash to delimit the
<i>RE</i>.
Within the
<i>RE</i>,
the
<i>RE</i>
delimiter itself can be used as a literal
character if it is preceded by a backslash.
<h5><a name = "tag_001_014_541_011">&nbsp;</a>Interactive Global Command</h5>
<pre>
<code>
<i>Synopsis</i>:	(1,$)G/<i>RE</i>/
</code>
</pre>
<p>
In the
<b>G</b>
command, the first step
is to mark every line that matches the given
<i>RE.</i>
Then, for every such line, that line will be written,
the current line number will be set to the address of that line, and any one
command (other than one of the
<b>a</b>,
<b>c</b>,
<b>i</b>,
<b>g</b>,
<b>G</b>,
<b>v</b>
and
<b>V</b>
commands)
can be input and will be executed.
A
newline character
acts as a null command
(causing no action to be taken on the current line);
an
<b>&amp;</b>
causes the reexecution
of the most recent non-null command executed within
the current invocation of
<b>G</b>.
Note that the commands input as part of the execution of the
<b>G</b>
command can address and affect any lines in the buffer.
The final value of the current line number will be the value set by
the last command successfully executed.
(Note that the last
command successfully executed will be the
<b>G</b>
command itself if a
command fails or the null command is specified.)
If there were
no matching lines, the current line number will not be changed.
The <b>G</b>
command can be terminated by a SIGINT signal.
Any character other than space or newline
can be used instead of a slash to delimit the
<i>RE</i>
and the replacement.
Within the
<i>RE</i>,
the
<i>RE</i>
delimiter itself can be used as a literal
character if it is preceded by a backslash.
<h5><a name = "tag_001_014_541_012">&nbsp;</a>Help Command</h5>
<pre>
<code>
<i>Synopsis</i>:	h
</code>
</pre>
<p>
The
<b>h</b>
command writes a short
message to standard output that explains
the reason for the most recent
<b>?</b>
notification.
The current line number is unchanged.
<h5><a name = "tag_001_014_541_013">&nbsp;</a>Help-mode Command</h5>
<pre>
<code>
<i>Synopsis</i>:	H
</code>
</pre>
<p>
The
<b>H</b>
command causes
<i>ed</i>
to enter a mode in which
help messages (see the
<b>h</b>
command) will be written to standard output for all subsequent
<b>?</b>
notifications.
The
<b>H</b>
command alternatively will turn this mode
on and off; it is initially off.
If the help-mode is being turned on, the
<b>H</b>
command also will explain the previous
<b>?</b>
notification, if there was one.
The current line number is unchanged.
<h5><a name = "tag_001_014_541_014">&nbsp;</a>Insert Command</h5>
<pre>
<code>
<i>Synopsis</i>:	(.)i
	&lt;<i>text</i>&gt;
	.
</code>
</pre>
<p>
The
<b>i</b>
command inserts the given text before the addressed line;
.
will be left at the last inserted line or, if there was none,
at the addressed line.
This command differs from the
<b>a</b>
command only in the placement of the input text.
Address 0 is invalid for this command.
<h5><a name = "tag_001_014_541_015">&nbsp;</a>Join Command</h5>
<pre>
<code>
<i>Synopsis</i>:	(.,.+1)j
</code>
</pre>
<p>
The
<b>j</b>
command joins contiguous lines by removing the appropriate
newline characters.
If exactly one address is given, this command will do nothing.
If lines are joined, the current line number will be set to the
address of the joined line; otherwise, the current line number
is unchanged.
<h5><a name = "tag_001_014_541_016">&nbsp;</a>Mark Command</h5>
<pre>
<code>
<i>Synopsis</i>:	(.)k<i>x</i>
</code>
</pre>
<p>
The
<b>m</b>
command marks the addressed line with name
<i>x</i>,
which must be a lower-case letter
from the portable character set.
The address
'x
then refers to this line;
the current line number
is unchanged.
<h5><a name = "tag_001_014_541_017">&nbsp;</a>List Command</h5>
<pre>
<code>
<i>Synopsis</i>:	(.,.)l
</code>
</pre>
<p>
The
<b>l</b>
command writes to standard output the addressed lines in a
visually unambiguous form.
The characters listed in the table in
the <b>XBD</b> specification, <a href="../xbd/notation.html"><b>File Format Notation</b>&nbsp;</a> 
(\\,
\a,
\b,
\f,
\r,
\t,
\v)
will be written as the corresponding escape sequence;
the
\n
in that table is not applicable.
Non-printable characters not in the table
will be written as one three-digit octal number
(with a preceding backslash character)
for each byte in the character (most significant byte first).
If the size of a byte on the system is greater than nine bits,
the format used for non-printable characters is implementation-dependent.
<p>
Long lines will be folded, with the point of
folding indicated by writing
backslash/newline character;
the length at which folding occurs is unspecified,
but should be appropriate for the output device.
The end of each line will be marked with a "$".
An
<b>l</b>
command can be appended to any other command
other than
<b>e</b>,
<b>E</b>,
<b>f</b>,
<b>q</b>,
<b>Q</b>,
<b>r</b>,
<b>w</b>
or
<b>!</b>.
The current line number will be set to the address of the last line written.
<h5><a name = "tag_001_014_541_018">&nbsp;</a>Move Command</h5>
<pre>
<code>
<i>Synopsis</i>:	(.,.)m<i>address</i>
</code>
</pre>
<p>
The
<b>m</b>
command repositions the addressed lines after the line
addressed by
<i>address</i>.
Address 0 is valid for
<i>address</i>
and causes the addressed lines to be moved to
the beginning of the buffer.
It is an error if address
<i>address</i>
falls within the range of moved lines.
The current line number will be set to the address of the last line moved.
<h5><a name = "tag_001_014_541_019">&nbsp;</a>Number Command</h5>
<pre>
<code>
<i>Synopsis</i>:	(.,.)n
</code>
</pre>
<p>
The
<b>n</b>
command writes to standard output the addressed lines,
preceding each line by its line number and a tab character;
the current line number will be set to the address of the last line written.
The
<b>n</b>
command can be appended to any command other than
<b>e</b>,
<b>E</b>,
<b>f</b>,
<b>q</b>,
<b>Q</b>,
<b>r</b>,
<b>w</b>
or
<b>!</b>.
<h5><a name = "tag_001_014_541_020">&nbsp;</a>Print Command</h5>
<pre>
<code>
<i>Synopsis</i>:	(.,.)p
</code>
</pre>
<p>
The
<b>p</b>
command writes to standard output the addressed lines;
the current line number will be set to the address of the last line written.
The
<b>p</b>