On Wed, Nov 14, 2012 at 6:26 PM, Larry Baker <baker@usgs.gov> wrote:

m4 --version | sed -n -E -e '1s/^.*[^A-Za-z0-9_-]?([0-9]+[.][0-9]+[.][0-9]+)[^A-Za-z0-9_-]?.*$/\1/p'

There are STILL problems with this approach as it is TWICE specific to GNU software:

1) M4 on OpenBSD (maybe others) doesn't support a "--version" flag:

$ m4 --version | sed -n -E -e '1s/^.*[^A-Za-z0-9_-]?([0-9]+[.][0-9]+[.][0-9]+)[^A-Za-z0-9_-]?.*$/\1/p'

m4: unknown option -- -

usage: m4 [-gPs] [-Dname[=value]] [-d flags] [-I dirname] [-o filename]

[-t macro] [-Uname] [file ...]

2) sed on Solaris (maybe others) doesn't support a "-E" flag:

$ m4 --version | sed -n -E -e '1s/^.*[^A-Za-z0-9_-]?([0-9]+[.][0-9]+[.][0-9]+)[^A-Za-z0-9_-]?.*$/\1/p'

/bin/sed: illegal option -- E

-Paul

Paul H. Hargrove PHHargrove@lbl.gov

Future Technologies Group

Computer and Data Sciences Department Tel: +1-510-495-2352

Lawrence Berkeley National Laboratory Fax: +1-510-486-6900