Replace dynamic content in XML file

Solution 1:

You can use xmlstarlet to edit a XML file in a shell like this :

xmlstarlet edit -L -u "/scs-shop/price[@type='double']" -v '99.66' file.xml

NOTE

• "/scs-shop/price[@type='double']" is a Xpath expression
• see xmlstarlet ed --help

Solution 2:

The XML way is cool, but if you need to use normal bash tools, you can modify a line using sed. For instance:

PRICE=123
sed -i "s/\(<price.*>\)[^<>]*\(<\/price.*\)/\1$PRICE\2/" $XML_FILE_TO_MODIFY

This will replace the price with 123.

That sed command seems daunting, so let me break it down:

\(<price.*>\)[^<>]*\(<\/price.*\) is the pattern to match. \( ... \) are parenthesis for grouping. <price.*> matches the opening price tag. [^<>]* matches anything except angle brackets, and in this case will match the contents of the price tag. <\/price.* matches the end of the price tag. Forward slash is a delimiter in sed, so I escape it with a back slash.

\1$PRICE\2 is the text to replace the matched text with. \1 refers to the first matched parenthesis group, which is the opening price tag. $PRICE is the variable with the desired price in it. \2 refers to the second parenthesis group, in this case the closing tag.

Solution 3:

I did not have the luxury of having xmlstarlet. I found a solution though simply by doing an inline replacement;

template-parameter.xml

<ns:Parameter>
    <ns:Name required="true">##-ParamName-##</ns:Name>
    <ns:Value>
        <ns:Text>##-ParamValue-##</ns:Text>
    </ns:Value>
</ns:Parameter>

Snippet

tokenName="foo"
tokenValue="bar"    

#Replace placeholders in parameter template element
myParamElement=$(cat template-parameter.xml)
myParamElement=${myParamElement//##-ParamName-##/$tokenName}
myParamElement=${myParamElement//##-ParamValue-##/$tokenValue}  

Result

<ns:Parameter>
    <ns:Name required="true">foo</ns:Name>
    <ns:Value>
        <ns:Text>bar</ns:Text>
    </ns:Value>
</ns:Parameter>