How to Wrap a file with Tags in Bash

Question

I have an xml file named test.xml, without a root tag like this:

<cat></cat>
<name></name>
<id></id>
<cat></cat>
<name></name>
<id></id>

How can I wrap this file with a root tag to make the output look like this:

<root>
  <cat></cat>
  <name></name>
  <id></id>
  <cat></cat>
  <name></name>
  <id></id>
</root>

Answer 1

In line number one insert before it (i\) the opening tag, and in last line ($) append after it (a\) the closing tag (I didn't care about the formatting with spaces):

EDIT: I forgot to say that GNU version of sed is needed.

Content of script.sed:

1 i\
<root>
$ a\
</root>

Run it like:

sed -f script.sed infile

With following output:

<root>
<cat></cat>
<name></name>
<id></id>
<cat></cat>
<name></name>
<id></id>
</root>

Answer 2

You can do this with redirection:

(echo "<root>"; cat test.xml; echo "</root>") > wrapped-test.xml

And with indention:

(echo "<root>"; sed 's/^/  /' test.xml; echo "</root>") > wrapped-test.xml