Test, validate and match regular expressions
Matches structured identifier strings composed of two alphanumeric codes joined by a slash (XX9999X/XX9999X99XXX pattern), followed by a 6-character token, a free-form word, a 4-digit number after a slash, and a trailing 4-digit number. Captures each segment into separate groups for extracting parts like document references, order codes, or batch identifiers from fixed-format records. The gm flags enable scanning multiple lines in a file.