I've asked this on comp.unix.shell, but never got a 100% satsifactory answer. Perhaps someone here might know. Does anyone know how to get the number of seconds since 1/1/1970 on a Unix system using the shell - not compiling C code. I can't assume the computer has perl, python or a C compiler. http://shell.cfajohnson.com/cus-faq.html#Q6 says: ------------------------------------------------------ - GNU date has the %s format option which returns the epoch time. - More portably, use awk. awk 'BEGIN {srand(); printf("%d\n", srand())}' This works because srand() sets its seed value with the current epoch time if not given an argument. It also returns the previous seed value, so the second call gives the epoch time. Note that this doesn't work with older versions of awk. This requires a version supporting the POSIX spec for srand(). For example, on Solaris this will not work with /usr/bin/awk, but will with nawk or /usr/xpg4/bin/awk. ------------------------------------------------------------- The problem is, from what I gather, POSIX only says the random number generator has to be seeded from the time, but not what time. Most awks use seconds since the epoch, but apparently OpenBSD does not. Someone has proposed that microseconds since midnight would be better. There appears to be no standard. The awk/srand method has worked for me on AIX, HP-UX, Linux, OS X and Solaris. For the purpose I have for this, leapseconds would be best ignored, though it is not essential they are. Dave

$ date +%s
1255442977

In message <286f7bad0910130703v6680affbx95905a440000099f@mail.gmail.com>, David Kirkby writes: >I've asked this on comp.unix.shell, but never got a 100% satsifactory >answer. Perhaps someone here might know. > >Does anyone know how to get the number of seconds since 1/1/1970 on a >Unix system using the shell - not compiling C code. I can't assume the >computer has perl, python or a C compiler. On FreeBSD you can use the strftime facility in date(1): $ date +%s 1255442977 Poul-Henning -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.

$ date +%s
1255442977

Poul-Henning Kamp escribió: > In message <286f7bad0910130703v6680affbx95905a440000099f@mail.gmail.com>, David > Kirkby writes: >> I've asked this on comp.unix.shell, but never got a 100% satsifactory >> answer. Perhaps someone here might know. >> >> Does anyone know how to get the number of seconds since 1/1/1970 on a >> Unix system using the shell - not compiling C code. I can't assume the >> computer has perl, python or a C compiler. > > On FreeBSD you can use the strftime facility in date(1): > > $ date +%s > 1255442977 > > Poul-Henning > And same works for linux, too Regards, Javier -- ------------------------------------------------------------------------ Javier Herrero EMAIL: jherrero@hvsistemas.com HV Sistemas S.L. PHONE: +34 949 336 806 Los Charcones, 17A FAX: +34 949 336 792 19170 El Casar - Guadalajara - Spain WEB: http://www.hvsistemas.com

2009/10/13 Poul-Henning Kamp <phk@phk.freebsd.dk>: > In message <286f7bad0910130703v6680affbx95905a440000099f@mail.gmail.com>, David >  Kirkby writes: >>I've asked this on comp.unix.shell, but never got a 100% satsifactory >>answer. Perhaps someone here might know. >> >>Does anyone know how to get the number of seconds since 1/1/1970 on a >>Unix system using the shell - not compiling C code. I can't assume the >>computer has perl, python or a C compiler. > > On FreeBSD you can use the strftime facility in date(1): > >        $ date +%s >        1255442977 > > Poul-Henning But it does not work on Solaris or HP-UX

FWIW it works on Darwin (MacOS X) which is BSD derived...

On Tue, Oct 13, 2009 at 10:14:56PM +0100, David Kirkby wrote: > 2009/10/13 Poul-Henning Kamp <phk@phk.freebsd.dk>: > > In message <286f7bad0910130703v6680affbx95905a440000099f@mail.gmail.com>, David > >  Kirkby writes: > >>I've asked this on comp.unix.shell, but never got a 100% satsifactory > >>answer. Perhaps someone here might know. > >> > >>Does anyone know how to get the number of seconds since 1/1/1970 on a > >>Unix system using the shell - not compiling C code. I can't assume the > >>computer has perl, python or a C compiler. > > > > On FreeBSD you can use the strftime facility in date(1): > > > >        $ date +%s > >        1255442977 > > > > Poul-Henning > But it does not work on Solaris or HP-UX FWIW it works on Darwin (MacOS X) which is BSD derived... -- Dave Emery N1PRE/AE, die@dieconsulting.com DIE Consulting, Weston, Mass 02493 "An empty zombie mind with a forlorn barely readable weatherbeaten 'For Rent' sign still vainly flapping outside on the weed encrusted pole - in celebration of what could have been, but wasn't and is not to be now either."