Question

I want to add an attribute to every tag in my xml, which is incrementing using either awk, sed, perl or plain shell cmd

For Eg:

<tag1 key="123">
  <tag2 abc="xf d"/>
  <tag3 def="d2 32">
   </tag3>
</tag1>

I am expecting the following output

<tag1 key="123" order="1">
  <tag2 abc="xf d" order="2"/>
  <tag3 def="d2 32" order="3">
   </tag3>
</tag1>

If possible I am not looking on any dependencies(Twig,LibXML), pure string manipulation.

Answer 1

Normally you should use a proper parser to process xml. But in awk:

awk 'match($0, /<[^\/>]+/) { \
     $0 = substr($0, 1, RSTART+RLENGTH-1) " order=\"" ++i "\"" \
          substr($0, RSTART+RLENGTH) \
     }; 1'

I look for a opening tag (without the > or /> part) on every the line. If found, put the string order="i" after it, while incrementing i. The single 1 on the last line just always executes awk‘s default action: { print $0 }.

I updated the regular expression to work on your revised input. It fails as soon as you have multiple opening tags on a single line, etc.