+ with \I0 in HeLlO WoRlD yields Hello WorldĪll literal text and all text inserted by replacement text tokens after \U up to the next \E or \L is converted to uppercase. Insert the whole regex match or the 1st through 99th backreference with the first letter of each word in the matched text converted to uppercase and the remaining letters converted to lowercase. + with \F0 in HeLlO WoRlD yields Hello world Insert the whole regex match or the 1st through 99th backreference with the first letter in the matched text converted to uppercase and the remaining letters converted to lowercase. + with \L0 in HeLlO WoRlD yields hello world Insert the whole regex match or the 1st through 99th backreference with all letters in the matched text converted to lowercase. + with \U0 in HeLlO WoRlD yields HELLO WORLD Insert the whole regex match or the 1st through 99th backreference with all letters in the matched text converted to uppercase. Replacing b with $POSTMATCH in abc yields acc
Insert the part of the subject string to the right of the regex match Replacing b with $PREMATCH in abc yields aac Insert the part of the subject string to the left of the regex match Replacement Strings Reference: Context and Case Conversion
