XML-SED
XML-SED
NAME
SYNOPSIS
DESCRIPTION
OPTIONS
EDITING COMMANDS
EXIT STATUS
EXAMPLE
BUGS
AUTHORS
SEE ALSO
NAME
xml-sed −
stream editor for filtering and transforming an XML
file.
SYNOPSIS
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xml-sed |
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[OPTION]... SCRIPT
[ [FILE] [:XPATH]... ] |
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DESCRIPTION
xml-sed
is a stream editor for XML files similar to sed(1).
It can be used to perform basic text and structural
transformations on an input FILE or the standard input, with
the results printed on the standard output. xml-sed
only makes a single pass through the input, and is
particularly suited for filtering XML documents in a
pipeline.
xml-sed
operates by first splitting its input into echo-leaves,
which are described in xml-coreutils(7) and should be
each thought of as analogous to a single line of text
processed by sed(1). As each echo-leaf is read, it is
placed in the pattern space, where editing commands can
operate. Once all editing has taken place, the pattern space
is printed in the manner of xml-echo(1), thus
converting the (now modified) echo-leaf into a real XML
fragment on the standard output. At this point, the next
echo-leaf is read and the cycle is repeated.
If one or more
XPATH(s) are present, then editing will only be performed on
the selected nodes, ie unselected nodes cannot be modified.
The case where no XPATH is present implicitly selects all
nodes for editing.
You may find
the following command useful initially to better understand
this process:
xml-sed --unecho ’’ myfile
Each editing
command in xml-sed consists of an (optional) address
followed by a command code. If no address is present, then
this command operates on each echo-leaf in turn, otherwise
it operates only on the echo-leaves which match the
address.
The simplest
address is a numerical range which applies to the input
ordering of the echo-leaves. The --unecho switch shows the
required ordinal numbers.
The single most
useful command is the ’s’ command, which
substitutes text within the echo-leaf. The syntax of the
’s’ command is identical to the ’s’
command of sed(1), but extends the available flags
slightly, to better adapt to the added structure of an
echo-leaf.
OPTIONS
--unecho
Print the pattern space as an
XML comment, just before the echo-leaf is output, but after
all editing commands have been performed. In addition to the
pattern space, the comment also includes the echo-leaf
number. Moreover, the selection status (if the node is
selected by an XPATH) is marked with a star.
EDITING COMMANDS
Each editing
command is optionally preceded by an address, which can take
the form NUM or NUM1,NUM2. In the first case, the command is
executed when the echo-leaf number is NUM, whereas in the
latter case the command is executed for all echo-leaves
numbered NUM1 (incl.) to NUM2 (excl.). The special symbol
"$" represents the number infinity. If no address
is specified, the command applies to all echo-leaves in the
input. If a block is preceded by an address, then that
address is used as a default for all commands within the
block.
#comment
The comment extends until the
end of the line.
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{ |
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Begin a block of commands. Must end with }. |
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} |
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End a block of commands. |
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a text |
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Append text after echo-leaf. Embedded newlines must be
quoted with backslash. |
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c text |
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Replace echo-leaf with text. Embedded newlines must be
quoted with backslash. |
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i text |
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Insert text before echo-leaf. Embedded newlines must be
quoted with backslash. |
b label
Branch to label, or end of
script if no label provided.
: label
Define label for b and t
commands.
t label
If a ’s’ command
has successfully substituted a pattern in the pattern space,
branch to label.
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d |
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Delete the whole pattern space and start next command
cycle from the beginning. |
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D |
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Delete the first echo-leaf in the pattern space and
start next command cycle. |
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h |
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Copy pattern space into hold space. |
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H |
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Append pattern space into hold space. |
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g |
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Copy hold space into pattern space. |
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G |
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Append hold space into pattern space. |
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l |
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Print the current pattern space as an echo-leaf wrapped
in an XML comment. |
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n |
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Read the next echo-leaf into the pattern space. |
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N |
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Append the next echo-leaf into the pattern space. |
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p |
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Print the current pattern space. |
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P |
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Print the first echo-leaf contained in the pattern
space. |
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q |
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Quit xml-sed, closing all open tags. |
s/regex/replacement/flags
If regex matches within the
pattern space, substitute the replacement. With no flags,
the match always skips the PATH section of the first
echo-leaf. With the x flag, the match applies only to the
PATH section of the first echo-leaf. With the z flag, the
match applies to the full pattern space.
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x |
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Swap the hold and pattern spaces. |
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y/source/dest/
Transliterate the characters in
source with the corresponding characters in dest.
EXIT STATUS
xml-sed returns
0 on success, or 1 otherwise.
EXAMPLE
Replace a tag
name:
cat notebook.xml | xml-sed ’s/root/book/x’
BUGS
The current
version of xml-sed doesn’t handle doctypes or
processing instructions.
AUTHORS
Laird
A. Breyer is the original author of this software. The
source code (GPLv3 or later) for the latest version is
available at the following locations:
http://www.lbreyer.com/gpl.html
http://xml-coreutils.sourceforge.net
SEE ALSO
xml-coreutils(7)
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