In the example i search for all lines which have less or more than 5 spaces as seperator. modify the valid nr of spaces: there are 3 (of 4) arbitrary groups wich have an specified nr of copies of an regEx in it: in the example the valid nr of entires is 5 : -> that means 4 spaces are valid in-bet...

National Provider Id (either facility or person)

It matches any one line of string that does not have only digit, space and dot(\x2e). If it has any character beside the aformentioned ones there is a match.

This regex capture only one of string that is a combination of number, dot and characters. It can also not have any number or dot, but must have at least one character

cat txt | sed 's/client_secret="[]"/client_secret="HEREHERE"/