# Grab regex group in powershell (e.g. version from string)

$STR="v0.1.1-prerelease-2"

$VERSION=[regex]::match($STR,'(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)').Groups[0].Value

# $VERSION will print 0.1.1

\d digit [0-9]

\w alpha numeric [a-zA-Z0-9_]

\s whitespace character

.  any character except newline

() sub-expression

\  escape the next character