Find and replace with reordered date format in notepad++

To make sure you only reorder wrong formats (in case you have mixed formats from merging databases), use this:

([0-9]{2})-+([0-9]{2})-+([0-9]{4})

This searches for (four digits, dash, two digits, dash, two digits).

In an regex capable editor like notepad++, replace it with this:

\3-\2-\1

In a tool like libre office, you need to replace it with this:

$3-$2-$1 

Edit: I wrote a blogpost about this as it seems to be a common problem: http://bytethinker.com/blog/correct-date-format-with-notepad-and-regex

Used Notepad++ to change mm/dd/yyyy to yyyy/mm/dd in several lines of a text file. Script was saved as a macro for next file.

Find: ([0-9]{2})/+([0-9]{2})/+([0-9]{4}) Replace: \3/\1/\2

You can do this with Textpad:

Find: ([0-9]+)-+([0-9]+)-+([0-9]+)

Replace: \3-\2-\1

Another robust pattern that works on ISO date format values like "2010-11-30T00:00:00.266Z "

Capturing groups of various elements of an ISO date representation

"(\d{4})-(\d{1,2})-(\d{1,2})T([0-2]\d):([0-5]\d):([0-5]\d)(?:.\d+)?Z?\s?"

In total six groups are being captured in this pattern, seventh group in the end containing '?:' is non-capturing, meaning it does not keep any value recorded by the group, simply ignores them.

The six groups we have captured have numbers based on positions such as \1 \2 \3... upto \6.

Replacement pattern to change that date into Database supported date format mostly used in Oracle values like - "11/30/2010 00:00:00 AM"

"\2/\3/\1 \4:\5:\6 AM"

It works well with Notepad++ Good Luck!