A few tips of Regex which can improve your efficiency on processing texts.

The Regex used here is PCRE.

Delete Empty Lines

Replace ^[ \t]*\r\n with empty string

Remove Heading Spaces of Each Line

Replace ^[ \t]+ with empty String

Remove Trailing Spaces of Each Line

Replace [ \t]+$ with empty string

Add Words to The Start of Each Line

Replace ^ with words you want to add

Add Words to The End of Each Line

Replace $ with words you want to add

Replace Value for a Tag in XML

For example, If you want replace <XMLTagName>Value</XMLTagName> with <XMLTagName>Value_New</XMLTagName>

Replace (<XMLTagName>)(.*)(</XMLTagName>) with $1$2_New$3