gsub("Today is([\\s\\S]*)", "My value\\1", "Today is a
great Day")
gsub("(?s)Today is(.*)", "My value\\1", "Today is a
great Day", perl=T)
Z3N1YigiVG9kYXkgaXMoW1xcc1xcU10qKSIsICJNeSB2YWx1ZVxcMSIsICJUb2RheSBpcyBhCmdyZWF0IERheSIpCgpnc3ViKCIoP3MpVG9kYXkgaXMoLiopIiwgIk15IHZhbHVlXFwxIiwgIlRvZGF5IGlzIGEKZ3JlYXQgRGF5IiwgcGVybD1UKQ==