Regex Editor & Tester

This pattern matches the literal word 'luong' followed by an optional colon and then another 'luong', i.e., it matches both 'luongluong' and 'luong:luong'. The character class [\:] is simply an escaped colon, so the escape is redundant. With global and multiline flags enabled, it finds every occurrence of these forms across all lines of text—useful for detecting repeated name patterns or simple key:value-style strings.