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<HTML>
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<HEAD>
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<!-- This HTML file has been created by texi2html 1.54
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from ../texi/sed.texi on 28 October 1999 -->
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|
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<TITLE>sed, a stream editor - sed Programs</TITLE>
|
||||
<link href="sed_4.html" rel=Next>
|
||||
<link href="sed_2.html" rel=Previous>
|
||||
<link href="sed_toc.html" rel=ToC>
|
||||
|
||||
</HEAD>
|
||||
<BODY>
|
||||
<p>Go to the <A HREF="sed_1.html">first</A>, <A HREF="sed_2.html">previous</A>, <A HREF="sed_4.html">next</A>, <A HREF="sed_9.html">last</A> section, <A HREF="sed_toc.html">table of contents</A>.
|
||||
<P><HR><P>
|
||||
|
||||
|
||||
<H1><A NAME="SEC3" HREF="sed_toc.html#TOC3">SED Programs</A></H1>
|
||||
|
||||
<P>
|
||||
<A NAME="IDX19"></A>
|
||||
<A NAME="IDX20"></A>
|
||||
A SED program consists of one or more SED commands,
|
||||
passed in by one or more of the
|
||||
<CODE>-e</CODE>, <CODE>-f</CODE>, <CODE>--expression</CODE>, and <CODE>--file</CODE>
|
||||
options, or the first non-option argument if zero of these
|
||||
options are used.
|
||||
This document will refer to "the" SED script;
|
||||
this will be understood to mean the in-order catenation
|
||||
of all of the <VAR>script</VAR>s and <VAR>script-file</VAR>s passed in.
|
||||
|
||||
</P>
|
||||
<P>
|
||||
Each SED command consists of an optional address or
|
||||
address range, followed by a one-character command name
|
||||
and any additional command-specific code.
|
||||
|
||||
</P>
|
||||
|
||||
|
||||
|
||||
<H2><A NAME="SEC4" HREF="sed_toc.html#TOC4">Selecting lines with SED</A></H2>
|
||||
<P>
|
||||
<A NAME="IDX21"></A>
|
||||
<A NAME="IDX22"></A>
|
||||
<A NAME="IDX23"></A>
|
||||
|
||||
</P>
|
||||
<P>
|
||||
Addresses in a SED script can be in any of the following forms:
|
||||
<DL COMPACT>
|
||||
|
||||
<DT><SAMP>`<VAR>number</VAR>'</SAMP>
|
||||
<DD>
|
||||
<A NAME="IDX24"></A>
|
||||
<A NAME="IDX25"></A>
|
||||
Specifying a line number will match only that line in the input.
|
||||
(Note that SED counts lines continuously across all input files.)
|
||||
|
||||
<DT><SAMP>`<VAR>first</VAR>~<VAR>step</VAR>'</SAMP>
|
||||
<DD>
|
||||
<A NAME="IDX26"></A>
|
||||
This GNU extension matches every <VAR>step</VAR>th line
|
||||
starting with line <VAR>first</VAR>.
|
||||
In particular, lines will be selected when there exists
|
||||
a non-negative <VAR>n</VAR> such that the current line-number equals
|
||||
<VAR>first</VAR> + (<VAR>n</VAR> * <VAR>step</VAR>).
|
||||
Thus, to select the odd-numbered lines,
|
||||
one would use <CODE>1~2</CODE>;
|
||||
to pick every third line starting with the second, <CODE>2~3</CODE> would be used;
|
||||
to pick every fifth line starting with the tenth, use <CODE>10~5</CODE>;
|
||||
and <CODE>50~0</CODE> is just an obscure way of saying <CODE>50</CODE>.
|
||||
|
||||
<DT><SAMP>`$'</SAMP>
|
||||
<DD>
|
||||
<A NAME="IDX27"></A>
|
||||
<A NAME="IDX28"></A>
|
||||
<A NAME="IDX29"></A>
|
||||
This address matches the last line of the last file of input.
|
||||
|
||||
<DT><SAMP>`/<VAR>regexp</VAR>/'</SAMP>
|
||||
<DD>
|
||||
<A NAME="IDX30"></A>
|
||||
<A NAME="IDX31"></A>
|
||||
This will select any line which matches the regular expression <VAR>regexp</VAR>.
|
||||
If <VAR>regexp</VAR> itself includes any <CODE>/</CODE> characters,
|
||||
each must be escaped by a backslash (<CODE>\</CODE>).
|
||||
|
||||
<DT><SAMP>`\%<VAR>regexp</VAR>%'</SAMP>
|
||||
<DD>
|
||||
(The <CODE>%</CODE> may be replaced by any other single character.)
|
||||
|
||||
<A NAME="IDX32"></A>
|
||||
This also matches the regular expression <VAR>regexp</VAR>,
|
||||
but allows one to use a different delimiter than <CODE>/</CODE>.
|
||||
This is particularly useful if the <VAR>regexp</VAR> itself contains
|
||||
a lot of <CODE>/</CODE>s, since it avoids the tedious escaping of every <CODE>/</CODE>.
|
||||
If <VAR>regexp</VAR> itself includes any delimiter characters,
|
||||
each must be escaped by a backslash (<CODE>\</CODE>).
|
||||
|
||||
<DT><SAMP>`/<VAR>regexp</VAR>/I'</SAMP>
|
||||
<DD>
|
||||
<DT><SAMP>`\%<VAR>regexp</VAR>%I'</SAMP>
|
||||
<DD>
|
||||
<A NAME="IDX33"></A>
|
||||
The <CODE>I</CODE> modifier to regular-expression matching is a GNU
|
||||
extension which causes the <VAR>regexp</VAR> to be matched in
|
||||
a case-insensitive manner.
|
||||
|
||||
</DL>
|
||||
|
||||
<P>
|
||||
If no addresses are given, then all lines are matched;
|
||||
if one address is given, then only lines matching that
|
||||
address are matched.
|
||||
|
||||
</P>
|
||||
<P>
|
||||
<A NAME="IDX34"></A>
|
||||
<A NAME="IDX35"></A>
|
||||
An address range can be specified by specifying two addresses
|
||||
separated by a comma (<CODE>,</CODE>).
|
||||
An address range matches lines starting from where the first
|
||||
address matches, and continues until the second address matches
|
||||
(inclusively).
|
||||
If the second address is a <VAR>regexp</VAR>, then checking for the
|
||||
ending match will start with the line <EM>following</EM> the
|
||||
line which matched the first address.
|
||||
If the second address is a <VAR>number</VAR> less than (or equal to)
|
||||
the line matching the first address,
|
||||
then only the one line is matched.
|
||||
|
||||
</P>
|
||||
<P>
|
||||
<A NAME="IDX36"></A>
|
||||
<A NAME="IDX37"></A>
|
||||
Appending the <CODE>!</CODE> character to the end of an address
|
||||
specification will negate the sense of the match.
|
||||
That is, if the <CODE>!</CODE> character follows an address range,
|
||||
then only lines which do <EM>not</EM> match the address range
|
||||
will be selected.
|
||||
This also works for singleton addresses,
|
||||
and, perhaps perversely, for the null address.
|
||||
|
||||
</P>
|
||||
|
||||
|
||||
|
||||
<H2><A NAME="SEC5" HREF="sed_toc.html#TOC5">Overview of regular expression syntax</A></H2>
|
||||
|
||||
<P>
|
||||
[[I may add a brief overview of regular expressions at a later date;
|
||||
for now see any of the various other documentations for regular
|
||||
expressions, such as the AWK info page.]]
|
||||
|
||||
</P>
|
||||
|
||||
|
||||
|
||||
<H2><A NAME="SEC6" HREF="sed_toc.html#TOC6">Where SED buffers data</A></H2>
|
||||
|
||||
<P>
|
||||
<A NAME="IDX38"></A>
|
||||
<A NAME="IDX39"></A>
|
||||
<A NAME="IDX40"></A>
|
||||
<A NAME="IDX41"></A>
|
||||
SED maintains two data buffers: the active <EM>pattern</EM> space,
|
||||
and the auxiliary <EM>hold</EM> space.
|
||||
In "normal" operation, SED reads in one line from the
|
||||
input stream and places it in the pattern space.
|
||||
This pattern space is where text manipulations occur.
|
||||
The hold space is initially empty, but there are commands
|
||||
for moving data between the pattern and hold spaces.
|
||||
|
||||
</P>
|
||||
|
||||
|
||||
|
||||
<H2><A NAME="SEC7" HREF="sed_toc.html#TOC7">Often used commands</A></H2>
|
||||
|
||||
<P>
|
||||
If you use SED at all, you will quite likely want to know
|
||||
these commands.
|
||||
|
||||
</P>
|
||||
<DL COMPACT>
|
||||
|
||||
<DT><SAMP>`#'</SAMP>
|
||||
<DD>
|
||||
[No addresses allowed.]
|
||||
|
||||
<A NAME="IDX42"></A>
|
||||
<A NAME="IDX43"></A>
|
||||
The <CODE>#</CODE> "command" begins a comment;
|
||||
the comment continues until the next newline.
|
||||
|
||||
<A NAME="IDX44"></A>
|
||||
If you are concerned about portability, be aware that
|
||||
some implementations of SED (which are not POSIX.2
|
||||
conformant) may only support a single one-line comment,
|
||||
and then only when the very first character of the script is a <CODE>#</CODE>.
|
||||
|
||||
<A NAME="IDX45"></A>
|
||||
<A NAME="IDX46"></A>
|
||||
Warning: if the first two characters of the SED script
|
||||
are <CODE>#n</CODE>, then the <CODE>-n</CODE> (no-autoprint) option is forced.
|
||||
If you want to put a comment in the first line of your script
|
||||
and that comment begins with the letter `n'
|
||||
and you do not want this behavior,
|
||||
then be sure to either use a capital `N',
|
||||
or place at least one space before the `n'.
|
||||
|
||||
<DT><SAMP>`s/<VAR>regexp</VAR>/<VAR>replacement</VAR>/<VAR>flags</VAR>'</SAMP>
|
||||
<DD>
|
||||
(The <CODE>/</CODE> characters may be uniformly replaced by
|
||||
any other single character within any given <CODE>s</CODE> command.)
|
||||
|
||||
<A NAME="IDX47"></A>
|
||||
<A NAME="IDX48"></A>
|
||||
<A NAME="IDX49"></A>
|
||||
The <CODE>/</CODE> character (or whatever other character is used in its stead)
|
||||
can appear in the <VAR>regexp</VAR> or <VAR>replacement</VAR>
|
||||
only if it is preceded by a <CODE>\</CODE> character.
|
||||
Also newlines may appear in the <VAR>regexp</VAR> using the two
|
||||
character sequence <CODE>\n</CODE>.
|
||||
|
||||
The <CODE>s</CODE> command attempts to match the pattern
|
||||
space against the supplied <VAR>regexp</VAR>.
|
||||
If the match is successful, then that portion of the pattern
|
||||
space which was matched is replaced with <VAR>replacement</VAR>.
|
||||
|
||||
<A NAME="IDX50"></A>
|
||||
<A NAME="IDX51"></A>
|
||||
The <VAR>replacement</VAR> can contain <CODE>\<VAR>n</VAR></CODE> (<VAR>n</VAR> being
|
||||
a number from 1 to 9, inclusive) references, which refer to
|
||||
the portion of the match which is contained between the <VAR>n</VAR>th
|
||||
<CODE>\(</CODE> and its matching <CODE>\)</CODE>.
|
||||
Also, the <VAR>replacement</VAR> can contain unescaped <CODE>&</CODE>
|
||||
characters which will reference the whole matched portion
|
||||
of the pattern space.
|
||||
To include a literal <CODE>\</CODE>, <CODE>&</CODE>, or newline in the final
|
||||
replacement, be sure to precede the desired <CODE>\</CODE>, <CODE>&</CODE>,
|
||||
or newline in the <VAR>replacement</VAR> with a <CODE>\</CODE>.
|
||||
|
||||
<A NAME="IDX52"></A>
|
||||
<A NAME="IDX53"></A>
|
||||
<A NAME="IDX54"></A>
|
||||
The <CODE>s</CODE> command can be followed with zero or more of the
|
||||
following <VAR>flags</VAR>:
|
||||
|
||||
<DL COMPACT>
|
||||
|
||||
<DT><SAMP>`g'</SAMP>
|
||||
<DD>
|
||||
<A NAME="IDX55"></A>
|
||||
<A NAME="IDX56"></A>
|
||||
Apply the replacement to <EM>all</EM> matches to the <VAR>regexp</VAR>,
|
||||
not just the first.
|
||||
<DT><SAMP>`p'</SAMP>
|
||||
<DD>
|
||||
<A NAME="IDX57"></A>
|
||||
If the substitution was made, then print the new pattern space.
|
||||
<DT><SAMP>`<VAR>number</VAR>'</SAMP>
|
||||
<DD>
|
||||
<A NAME="IDX58"></A>
|
||||
Only replace the <VAR>number</VAR>th match of the <VAR>regexp</VAR>.
|
||||
<DT><SAMP>`w <VAR>file-name</VAR>'</SAMP>
|
||||
<DD>
|
||||
<A NAME="IDX59"></A>
|
||||
If the substitution was made, then write out the result to the named file.
|
||||
<DT><SAMP>`I'</SAMP>
|
||||
<DD>
|
||||
(This is a GNU extension.)
|
||||
|
||||
<A NAME="IDX60"></A>
|
||||
<A NAME="IDX61"></A>
|
||||
Match <VAR>regexp</VAR> in a case-insensitive manner.
|
||||
</DL>
|
||||
|
||||
<DT><SAMP>`q'</SAMP>
|
||||
<DD>
|
||||
[At most one address allowed.]
|
||||
|
||||
<A NAME="IDX62"></A>
|
||||
<A NAME="IDX63"></A>
|
||||
Exit SED without processing any more commands or input.
|
||||
Note that the current pattern space is printed
|
||||
if auto-print is not disabled.
|
||||
|
||||
<DT><SAMP>`d'</SAMP>
|
||||
<DD>
|
||||
<A NAME="IDX64"></A>
|
||||
<A NAME="IDX65"></A>
|
||||
Delete the pattern space;
|
||||
immediately start next cycle.
|
||||
|
||||
<DT><SAMP>`p'</SAMP>
|
||||
<DD>
|
||||
<A NAME="IDX66"></A>
|
||||
<A NAME="IDX67"></A>
|
||||
Print out the pattern space (to the standard output).
|
||||
This command is usually only used in conjunction with the <CODE>-n</CODE>
|
||||
command-line option.
|
||||
|
||||
<A NAME="IDX68"></A>
|
||||
Note: some implementations of SED, such as this one, will
|
||||
double-print lines when auto-print is not disabled and the <CODE>p</CODE>
|
||||
command is given.
|
||||
Other implementations will only print the line once.
|
||||
Both ways conform with the POSIX.2 standard, and so neither
|
||||
way can be considered to be in error.
|
||||
<A NAME="IDX69"></A>
|
||||
Portable SED scripts should thus avoid relying on either behavior;
|
||||
either use the <CODE>-n</CODE> option and explicitly print what you want,
|
||||
or avoid use of the <CODE>p</CODE> command (and also the <CODE>p</CODE> flag to the
|
||||
<CODE>s</CODE> command).
|
||||
|
||||
<DT><SAMP>`n'</SAMP>
|
||||
<DD>
|
||||
<A NAME="IDX70"></A>
|
||||
<A NAME="IDX71"></A>
|
||||
<A NAME="IDX72"></A>
|
||||
If auto-print is not disabled, print the pattern space,
|
||||
then, regardless, replace the pattern space with the next line of input.
|
||||
If there is no more input then SED exits without processing
|
||||
any more commands.
|
||||
|
||||
<DT><SAMP>`{ <VAR>commands</VAR> }'</SAMP>
|
||||
<DD>
|
||||
<A NAME="IDX73"></A>
|
||||
<A NAME="IDX74"></A>
|
||||
<A NAME="IDX75"></A>
|
||||
A group of commands may be enclosed between
|
||||
<CODE>{</CODE> and <CODE>}</CODE> characters.
|
||||
(The <CODE>}</CODE> must appear in a zero-address command context.)
|
||||
This is particularly useful when you want a group of commands
|
||||
to be triggered by a single address (or address-range) match.
|
||||
|
||||
</DL>
|
||||
|
||||
|
||||
|
||||
<H2><A NAME="SEC8" HREF="sed_toc.html#TOC8">Less frequently used commands</A></H2>
|
||||
|
||||
<P>
|
||||
Though perhaps less frequently used than those in the previous
|
||||
section, some very small yet useful SED scripts can be built with
|
||||
these commands.
|
||||
|
||||
</P>
|
||||
<DL COMPACT>
|
||||
|
||||
<DT><SAMP>`y/<VAR>source-chars</VAR>/<VAR>dest-chars</VAR>/'</SAMP>
|
||||
<DD>
|
||||
(The <CODE>/</CODE> characters may be uniformly replaced by
|
||||
any other single character within any given <CODE>y</CODE> command.)
|
||||
|
||||
<A NAME="IDX76"></A>
|
||||
<A NAME="IDX77"></A>
|
||||
Transliterate any characters in the pattern space which match
|
||||
any of the <VAR>source-chars</VAR> with the corresponding character
|
||||
in <VAR>dest-chars</VAR>.
|
||||
|
||||
Instances of the <CODE>/</CODE> (or whatever other character is used in its stead),
|
||||
<CODE>\</CODE>, or newlines can appear in the <VAR>source-chars</VAR> or <VAR>dest-chars</VAR>
|
||||
lists, provide that each instance is escaped by a <CODE>\</CODE>.
|
||||
The <VAR>source-chars</VAR> and <VAR>dest-chars</VAR> lists <EM>must</EM>
|
||||
contain the same number of characters (after de-escaping).
|
||||
|
||||
<DT><SAMP>`a\'</SAMP>
|
||||
<DD>
|
||||
<DT><SAMP>`<VAR>text</VAR>'</SAMP>
|
||||
<DD>
|
||||
[At most one address allowed.]
|
||||
|
||||
<A NAME="IDX78"></A>
|
||||
<A NAME="IDX79"></A>
|
||||
<A NAME="IDX80"></A>
|
||||
Queue the lines of text which follow this command
|
||||
(each but the last ending with a <CODE>\</CODE>,
|
||||
which will be removed from the output)
|
||||
to be output at the end of the current cycle,
|
||||
or when the next input line is read.
|
||||
|
||||
<DT><SAMP>`i\'</SAMP>
|
||||
<DD>
|
||||
<DT><SAMP>`<VAR>text</VAR>'</SAMP>
|
||||
<DD>
|
||||
[At most one address allowed.]
|
||||
|
||||
<A NAME="IDX81"></A>
|
||||
<A NAME="IDX82"></A>
|
||||
<A NAME="IDX83"></A>
|
||||
Immediately output the lines of text which follow this command
|
||||
(each but the last ending with a <CODE>\</CODE>,
|
||||
which will be removed from the output).
|
||||
|
||||
<DT><SAMP>`c\'</SAMP>
|
||||
<DD>
|
||||
<DT><SAMP>`<VAR>text</VAR>'</SAMP>
|
||||
<DD>
|
||||
<A NAME="IDX84"></A>
|
||||
<A NAME="IDX85"></A>
|
||||
<A NAME="IDX86"></A>
|
||||
Delete the lines matching the address or address-range,
|
||||
and output the lines of text which follow this command
|
||||
(each but the last ending with a <CODE>\</CODE>,
|
||||
which will be removed from the output)
|
||||
in place of the last line
|
||||
(or in place of each line, if no addresses were specified).
|
||||
A new cycle is started after this command is done,
|
||||
since the pattern space will have been deleted.
|
||||
|
||||
<DT><SAMP>`='</SAMP>
|
||||
<DD>
|
||||
[At most one address allowed.]
|
||||
|
||||
<A NAME="IDX87"></A>
|
||||
<A NAME="IDX88"></A>
|
||||
<A NAME="IDX89"></A>
|
||||
Print out the current input line number (with a trailing newline).
|
||||
|
||||
<DT><SAMP>`l'</SAMP>
|
||||
<DD>
|
||||
<A NAME="IDX90"></A>
|
||||
<A NAME="IDX91"></A>
|
||||
<A NAME="IDX92"></A>
|
||||
Print the pattern space in an unambiguous form:
|
||||
non-printable characters (and the <CODE>\</CODE> character)
|
||||
are printed in C-style escaped form;
|
||||
long lines are split, with a trailing <CODE>\</CODE> character
|
||||
to indicate the split; the end of each line is marked
|
||||
with a <CODE>$</CODE>.
|
||||
|
||||
<DT><SAMP>`r <VAR>filename</VAR>'</SAMP>
|
||||
<DD>
|
||||
[At most one address allowed.]
|
||||
|
||||
<A NAME="IDX93"></A>
|
||||
<A NAME="IDX94"></A>
|
||||
<A NAME="IDX95"></A>
|
||||
Queue the contents of <VAR>filename</VAR> to be read and
|
||||
inserted into the output stream at the end of the current cycle,
|
||||
or when the next input line is read.
|
||||
Note that if <VAR>filename</VAR> cannot be read, it is treated as
|
||||
if it were an empty file, without any error indication.
|
||||
|
||||
<DT><SAMP>`w <VAR>filename</VAR>'</SAMP>
|
||||
<DD>
|
||||
<A NAME="IDX96"></A>
|
||||
<A NAME="IDX97"></A>
|
||||
Write the pattern space to <VAR>filename</VAR>.
|
||||
The <VAR>filename</VAR> will be created (or truncated) before the
|
||||
first input line is read; all <CODE>w</CODE> commands (including
|
||||
instances of <CODE>w</CODE> flag on successful <CODE>s</CODE> commands)
|
||||
which refer to the same <VAR>filename</VAR> are output through
|
||||
the same FILE stream.
|
||||
|
||||
<DT><SAMP>`D'</SAMP>
|
||||
<DD>
|
||||
<A NAME="IDX98"></A>
|
||||
<A NAME="IDX99"></A>
|
||||
Delete text in the pattern space up to the first newline.
|
||||
If any text is left, restart cycle with the resultant
|
||||
pattern space (without reading a new line of input),
|
||||
otherwise start a normal new cycle.
|
||||
|
||||
<DT><SAMP>`N'</SAMP>
|
||||
<DD>
|
||||
<A NAME="IDX100"></A>
|
||||
<A NAME="IDX101"></A>
|
||||
<A NAME="IDX102"></A>
|
||||
Add a newline to the pattern space,
|
||||
then append the next line of input to the pattern space.
|
||||
If there is no more input then SED exits without processing
|
||||
any more commands.
|
||||
|
||||
<DT><SAMP>`P'</SAMP>
|
||||
<DD>
|
||||
<A NAME="IDX103"></A>
|
||||
<A NAME="IDX104"></A>
|
||||
Print out the portion of the pattern space up to the first newline.
|
||||
|
||||
<DT><SAMP>`h'</SAMP>
|
||||
<DD>
|
||||
<A NAME="IDX105"></A>
|
||||
<A NAME="IDX106"></A>
|
||||
<A NAME="IDX107"></A>
|
||||
<A NAME="IDX108"></A>
|
||||
Replace the contents of the hold space with the contents of the pattern space.
|
||||
|
||||
<DT><SAMP>`H'</SAMP>
|
||||
<DD>
|
||||
<A NAME="IDX109"></A>
|
||||
<A NAME="IDX110"></A>
|
||||
<A NAME="IDX111"></A>
|
||||
Append a newline to the contents of the hold space,
|
||||
and then append the contents of the pattern space to that of the hold space.
|
||||
|
||||
<DT><SAMP>`g'</SAMP>
|
||||
<DD>
|
||||
<A NAME="IDX112"></A>
|
||||
<A NAME="IDX113"></A>
|
||||
<A NAME="IDX114"></A>
|
||||
<A NAME="IDX115"></A>
|
||||
Replace the contents of the pattern space with the contents of the hold space.
|
||||
|
||||
<DT><SAMP>`G'</SAMP>
|
||||
<DD>
|
||||
<A NAME="IDX116"></A>
|
||||
<A NAME="IDX117"></A>
|
||||
<A NAME="IDX118"></A>
|
||||
Append a newline to the contents of the pattern space,
|
||||
and then append the contents of the hold space to that of the pattern space.
|
||||
|
||||
<DT><SAMP>`x'</SAMP>
|
||||
<DD>
|
||||
<A NAME="IDX119"></A>
|
||||
<A NAME="IDX120"></A>
|
||||
<A NAME="IDX121"></A>
|
||||
Exchange the contents of the hold and pattern spaces.
|
||||
|
||||
</DL>
|
||||
|
||||
|
||||
|
||||
<H2><A NAME="SEC9" HREF="sed_toc.html#TOC9">Commands for die-hard SED programmers</A></H2>
|
||||
|
||||
<P>
|
||||
In most cases, use of these commands indicates that you are
|
||||
probably better off programming in something like PERL.
|
||||
But occasionally one is committed to sticking with SED,
|
||||
and these commands can enable one to write quite convoluted
|
||||
scripts.
|
||||
|
||||
</P>
|
||||
<P>
|
||||
<A NAME="IDX122"></A>
|
||||
<DL COMPACT>
|
||||
|
||||
<DT><SAMP>`: <VAR>label</VAR>'</SAMP>
|
||||
<DD>
|
||||
[No addresses allowed.]
|
||||
|
||||
<A NAME="IDX123"></A>
|
||||
<A NAME="IDX124"></A>
|
||||
Specify the location of <VAR>label</VAR> for the <CODE>b</CODE> and <CODE>t</CODE> commands.
|
||||
In all other respects, a no-op.
|
||||
|
||||
<DT><SAMP>`b <VAR>label</VAR>'</SAMP>
|
||||
<DD>
|
||||
<A NAME="IDX125"></A>
|
||||
<A NAME="IDX126"></A>
|
||||
<A NAME="IDX127"></A>
|
||||
Unconditionally branch to <VAR>label</VAR>.
|
||||
The <VAR>label</VAR> may be omitted, in which case the next cycle is started.
|
||||
|
||||
<DT><SAMP>`t <VAR>label</VAR>'</SAMP>
|
||||
<DD>
|
||||
<A NAME="IDX128"></A>
|
||||
<A NAME="IDX129"></A>
|
||||
<A NAME="IDX130"></A>
|
||||
Branch to <VAR>label</VAR> only if there has been a successful <CODE>s</CODE>ubstitution
|
||||
since the last input line was read or <CODE>t</CODE> branch was taken.
|
||||
The <VAR>label</VAR> may be omitted, in which case the next cycle is started.
|
||||
|
||||
</DL>
|
||||
|
||||
<P><HR><P>
|
||||
<p>Go to the <A HREF="sed_1.html">first</A>, <A HREF="sed_2.html">previous</A>, <A HREF="sed_4.html">next</A>, <A HREF="sed_9.html">last</A> section, <A HREF="sed_toc.html">table of contents</A>.
|
||||
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|
||||
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|
||||
Reference in New Issue
Block a user