How to insert a newline character after each occurrence of a specific XML tag in a file?

Tried in python

cat inputfile

san</Data>abhi</Data>san

Python

#!/usr/bin/python
g="</Data>"
import re
k=open('k.txt','r')
for i in k:
    m="{0}".format(g+"n")
    q=re.sub(g,"{0}",i).format(m)
    print q

output

san</Data>
abhi</Data>
san

sed 's:</Data>:&
:g'

Or when calling sed from bash or other shell that supports $'<char>' to expand an escape sequence:

sed 's:</Data>:&'$'n'':g'

Or with GNU sed:

sed 's:</Data>:&n:g'

e.g.:

$ printf 'foo</Data>bar</Data>etcn'
foo</Data>bar</Data>etc
$
$ printf 'foo</Data>bar</Data>etcn' | sed 's:</Data>:&n:g'
foo</Data>
bar</Data>
etc

Instead of just formatting the Data tag, you can format the whole XML file with newlines after each XML nodes. This is the proper solution.

Using sed is not elegant and not universal nor a proper solution.

Think of a CDATA section from within your XML with:

<![CDATA[foobar</Data>qux]]>

Instead, using an XML parser like xmlstarlet:

xmlstarlet format -R file.xml

Example:

cat file.xml
<foo>
<a>jkj</a><data>fghj</data><x>w</x>
</foo>

$ xmlstarlet fo -R file
<?xml version="1.0"?>
<foo>
  <a>jkj</a>
  <data>fghj</data>
  <x>w</x>
</foo>

sed '/</Data>/ a \n' will insert the newline, however, if the string exists more than once in a line (typical xml may be one long line) it simply appends a newline after it instead of after every occurrence.

If you really want a newline after every occurrence, sed 's/(</Data>)/1n/g' should do the trick.

This might not be the most elegant but it works:

sed 's/(</Data>)/1n/ig'