# 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