[colug-432] my shell is better^H^H^H^H^H^Hdifferent than yours: NSFW (but not for the reason you might think)

[Eric Floehr]

None manually set.  All returned the same result as my 256MB Synology NAS...

> ulimit -a | grep -i memory
memory(kb)           unlimited
locked memory(kb)    64
vmemory(kb)          unlimited

... except for the OpenSUSE instance:

> ulimit -a | grep -i memory
max locked memory       (kbytes, -l) 64
max memory size         (kbytes, -m) 651780
virtual memory          (kbytes, -v) 1538320

-Eric


On Tue, Dec 6, 2011 at 10:50 AM, Jon Miller <jonebird at gmail.com> wrote:

> Any memory limits set during any of the tests? (ulimit -a | grep -i memory)
>
> -- Jon Miller
>
> On Tue, Dec 6, 2011 at 10:45 AM, Eric Floehr <eric at intellovations.com>
> wrote:
> > On a 1GB Fedora 16 XFCE instance I had lying around (kernel
> > 3.1.0-0.rc6.git0.3.fc16.i686):
> >
> >
> > $ time bash -c "read line < /dev/zero"
> > bash: xrealloc: cannot allocate 1023406192 bytes (24576 bytes allocated)
> >
> > real    0m24.726s
> > user    0m7.219s
> > sys    0m12.226s
> >
> > A 768MB OpenSUSE 12.1 PR5 stock install:
> >
> >
> >> time bash -c "read line < /dev/zero"
> > bash: xrealloc: cannot allocate 1570377840 bytes (40960 bytes allocated)
> >
> > real    0m30.079s
> > user    0m9.693s
> > sys    0m10.197s
> >
> > And finally a 512MB LMDE XFCE stock install:
> >
> >
> > $ time bash -c "read line < /dev/zero"
> > bash: xrealloc: ../../bash/builtins/../../bash/builtins/read.def:525:
> cannot
> > allocate 536871024 bytes (1073770496 bytes allocated)
> >
> > real    0m20.388s
> > user    0m4.284s
> > sys    0m8.017s
> >
> >
> > Since I was feeling completely adventurous, I proceeded to shell into my
> > 256MB Synology NAS which is running 2.6.32.12 kernel:
> >
> >
> >> time bash -c "read line < /dev/zero"
> > bash: xrealloc: ./read.def:444: cannot reallocate 268435568 bytes (0
> bytes
> > allocated)
> > Command exited with non-zero status 2
> > real    0m 36.27s
> > user    0m 23.74s
> > sys     0m 3.28s
> >
> >
> > So appears to work on a modern Linux distro all the way down to 256MB.
> >
> > -Eric
> >
> >
> >
> > On Tue, Dec 6, 2011 at 10:22 AM, Judd Montgomery <judd at jpilot.org>
> wrote:
> >>
> >> On Tue, Dec 06, 2011 at 08:39:40AM -0500, Jeff Frontz wrote:
> >> > On the AST (AT&T Software Technology) user's mailing list, Glen Fowler
> >> > recently posted this snippet:
> >> >
> >> > > ... the seemingly good idea of "no limits" is not always a good idea
> >> > > proof of concept: try this with bash on a system that you can reboot
> >> > > with a physical button:
> >> > >
> >> > >        bash -c 'read line < /dev/zero'
> >> > >
> >> >
> >> > The context was why doesn't ksh let you read an arbitrarily long line
> of
> >> > text with the built-in "read" command (and why that limitation is on
> >> > purpose, but unfortunately undocumented).
> >> >
> >> >
> >> > Jeff
> >> >
> >> >
> >> I'll call the bluff and try it on a machine with 8 GB of RAM, 5 PDF
> >> files open, 20 or so terminals, 12 ssh sessions, lots of command
> >> histories, email, and browsers.
> >>
> >> $ time bash -c "read line < /dev/zero"
> >> bash: xrealloc: ../../bash/builtins/../../bash/builtins/read.def:525:
> >> cannot allocate 18446744071562068080 bytes (4295020544 bytes allocated)
> >>
> >> real    0m29.841s
> >> user    0m26.120s
> >> sys     0m3.720s
> >>
> >> What am I supposed to do with the power button?  Maybe it would crush
> >> a machine with less RAM, but I suspect the Linux kernel would kill the
> >> process on a low RAM machine (which is a gripe some have).  Anyone
> >> want to try?  I could in a VM.
> >>
> >> Does Glen have a problem with languages like C and assembly that give
> >> the programmer too much power?  Does he approve of Java because it
> >> prevents the programmer from doing "bad things?"
> >>
> >> Judd
> >> _______________________________________________
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> >> http://lists.colug.net/mailman/listinfo/colug-432
> >
> >
> >
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>
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