Hi
Well the use of "-" to represent stdin became more or less standard a long
time ago, although I guess it was always a "Unix" hack when compared to the
POSIX standards. But I  am surprised that this is not allowed for in ksh.

Pete


On 20 June 2014 17:09, Nathan Weeks <[email protected]> wrote:

> The ksh builtin grep apparently doesn't support "-" as an
> option-argument to the -f option:
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> $ cut -f 1 -d ' ' pattern_file | grep -Ff - file
> grep: -: cannot open [No such file or directory]
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> From my interpretation of POSIX.1-2008, it doesn't look like the -f
> option is required to support reading the pattern_file from standard
> input in the event of an "-" option-argument. bsdgrep (at least the
> version in FreeBSD 9.2) and /usr/xpg4/bin/grep from Solaris 11.2-beta
> also don't support it, though GNU grep does.
>
> --
> Nathan Weeks
> IT Specialist
> USDA-ARS Corn Insects and Crop Genetics Research Unit
> Crop Genome Informatics Laboratory
> Iowa State University
> http://weeks.public.iastate.edu/
>
>
>
> On Fri, Jun 20, 2014 at 11:00 AM,
> <[email protected]> wrote:
> > Message: 3
> > Date: Fri, 20 Jun 2014 15:54:54 +0100
> > From: Peter Hitchman <[email protected]>
> > Cc: AST / Korn Shell Users List <[email protected]>
> > Subject: Re: [ast-users] ksh hang on pipeline with builtin cut and
> >         grep
> > Message-ID:
> >         <CAK7tHSzCpDSiPFSmCCu93DDS6daVoCPe0ih_pjkheLV=
> [email protected]>
> > Content-Type: text/plain; charset="utf-8"
> >
> > Hi
> > How about instead of /dev/stdin you just use a "-"?
> >
> > e.g. cut -f 1 -d ' ' pattern_file | grep -Ff - file
> >
> > Regards
> > Pete
> >
> >
> > On 20 June 2014 15:41, Nathan Weeks <[email protected]> wrote:
> >
> >> I'm seeing a rather odd hang with ksh 2014-06-06 on OS X 10.7.5 when
> using
> >> the builtin cut and grep in a pipeline:
> >>
> >> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >> $ type cut
> >> cut is a shell builtin version of /usr/bin/cut
> >> $ type grep
> >> grep is a shell builtin version of /usr/bin/grep
> >> $ cat pattern_file
> >> x11 x12
> >> $ cat file
> >> x11
> >> x21
> >> $ cut -f 1 -d ' ' pattern_file | grep -Ff /dev/stdin file
> >> ...hang...
> >> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >>
> >> Using dtrace to get a stack trace of the ksh process during the hang
> >> reveals
> >> the following:
> >>
> >> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >> $ sudo dtruss -sp 7646
> >> Password:
> >> SYSCALL(args)            = return
> >> mmap(0x1E0962C49000, 0x700800000, 0x3, 0x1002, 0xFFFFFFFF, 0x6)
> >>   = 0x62C49000 0
> >>
> >>               libsystem_kernel.dylib`__mmap+0xa
> >>               ksh`_vmsegalloc+0x5b4
> >>               ksh`bestpackextend+0x1fb
> >>               ksh`bestpackalloc+0x379
> >>               ksh`bestalloc+0x245
> >>               ksh`bestresize+0x7d2
> >>               ksh`_ast_realloc+0x117
> >>               ksh`_sfexcept+0x3ff
> >>               ksh`sfwr+0x75a
> >>               ksh`_sfflsbuf+0x1b5
> >>               ksh`sfputr+0x1f8
> >>               ksh`addre+0x301
> >>               ksh`compile+0x2fe
> >>               ksh`grep+0xb0f
> >>               ksh`b_grep+0x1d2
> >>               ksh`sh_exec+0x2286
> >>               ksh`sh_exec+0x467a
> >>               ksh`sh_exec+0x53e8
> >>               ksh`exfile+0xe5b
> >>               ksh`sh_main+0x126a
> >> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >>
> >> --
> >> Nathan Weeks
> >> IT Specialist
> >> USDA-ARS Corn Insects and Crop Genetics Research Unit
> >> Crop Genome Informatics Laboratory
> >> Iowa State University
> >> http://weeks.public.iastate.edu/
> >> _______________________________________________
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