parsing - how to edit XML using bash script?

Question

<root>
<tag>1</tag>
<tag1>2</tag1>
</root>

Need to change values 1 and 2 from bash

Answer 1

To change tag's value to 2 and tag1's value to 3, using XMLStarlet:

xmlstarlet ed 
  -u '/root/tag' -v 2 
  -u '/root/tag1' -v 3 
  <old.xml >new.xml

---

Using your sample input:

xmlstarlet ed 
  -u '/root/tag' -v 2 
  -u '/root/tag1' -v 3 
  <<<'<root><tag>1</tag><tag1>2</tag1></root>'

...emits as output:

<?xml version="1.0"?>
<root>
  <tag>2</tag>
  <tag1>3</tag1>
</root>