Explore, test, and check regular expressions in the terminal.

Given your regular expression and text, crex will output matches,
capture groups, and details.  crex has a range of options, allowing
fine grained control over matching and output.  It uses ECMAScript
grammar by default, while also accepting posix, extended posix,
awk, grep, and extended grep grammars.  Input can be received by
piped stdin, or by using the -s option.  Output options include
plain, colour, and json formats.