On 7 April 2018 at 07:39, J Doe <gene...@nativemethods.com> wrote: > Hi Viktor and Dominic, > > If I do the following on Ubuntu 16.04 LTS: > > $ echo "1 2" | egrep '[[:digit:]]\s[[:digit:]]’ > 1 2 > > … where “1 2” are highlighted in bash > > Am I correct that since this POSIX regex for the digits AND the \s is > still being interpreted, my system must support the GNU regex extensions ?
It is standard Ubuntu it will support GNU regex extensions, but why not use pcre? It is more powerful, more standardised, and - my impression - more widely used for Postfix tables. Just do: $ sudo apt-get install postfix-pcre
