Bash insert subnode to XML file

Question

Im trying to edit a config file using bash. My file looks like this:

<configuration>
  <property>
    <name></name>
    <value></value>
  </property>
  <property>
    <name></name>
    <value></value>
  </property>
</configuration>

I want to add another couple of <property> blocks to the file. Since all property tags are enclosed inside the configuration tags the file would looks like this:

<configuration>
  <property>
    <name></name>
    <value></value>
  </property>
  <property>
    <name></name>
    <value></value>
  </property>
  <property>
    <name></name>
    <value></value>
  </property>
</configuration>

I came across this post and followed the accepted answer, however nothing is appended to my file and the xml block I try to append is "echo-ed" as a single line string. My bash file looks like this:

file=/path/to/file/oozie-site.xml
content="<property>\n<name></name>\n<value></value>\n</property>\n<property>\n<name></name>\n<value></value>\n</property>"
echo $content
C=$(echo $content | sed 's/\//\\\//g')
sed "/<\/configuration>/ s/.*/${C}\n&/" $file

Answer 1

With xmlstarlet:

xmlstarlet edit --omit-decl \
  -s '//configuration' -t elem -n "property" \
  -s '//configuration/property[last()]' -t elem -n "name" \
  -s '//configuration/property[last()]' -t elem -n "value" \
  file.xml

Output:

<configuration>
  <property>
    <name/>
    <value/>
  </property>
  <property>
    <name/>
    <value/>
  </property>
  <property>
    <name/>
    <value/>
  </property>
</configuration>

---

--omit-decl: omit XML declaration

-s: add a subnode (see xmlstarlet edit for details)

-t elem: set node type, here: element

-n: set name of element

Answer 2

Change the last line by sed -i.BAK "/<\/configuration>/ s/.*/${C}\n&/" $file