Hello Michael,
On Tue, Jun 06, 2017 at 06:49:08PM +0200, Michael Olbrich wrote:
> On Tue, Jun 06, 2017 at 06:25:09PM +0200, Uwe Kleine-König wrote:
> > On Tue, Jun 06, 2017 at 06:00:51PM +0200, Michael Olbrich wrote:
> > > On Tue, Jun 06, 2017 at 05:28:48PM +0200, Gavin Schenk wrote:
> > > > rc-once ist based on systemd offline update mechanism.
> > > > https://www.freedesktop.org/software/systemd/man/systemd.offline-updates
> > > >
> > > > To make it possible to have multiple update services beside rc-once the
> > > > script should check where the link /system-update points to.
> > > >
> > > > rc-once will only run if the link points to etc/rc-once.d or
> > > > /etc/rc-once.d.
> > > >
> > > > Signed-off-by: Gavin Schenk <g.sch...@eckelmann.de>
> > > > ---
> > > > projectroot/usr/lib/init/rc-once.sh | 5 +++++
> > > > rules/rc-once.in | 3 +++
> > > > 2 files changed, 8 insertions(+)
> > > >
> > > > diff --git a/projectroot/usr/lib/init/rc-once.sh
> > > > b/projectroot/usr/lib/init/rc-once.sh
> > > > index 8689a32bc..d225ad5c2 100644
> > > > --- a/projectroot/usr/lib/init/rc-once.sh
> > > > +++ b/projectroot/usr/lib/init/rc-once.sh
> > > > @@ -6,6 +6,11 @@ STAMP="$DONE_DIR/rc-once"
> > > >
> > > > run_rc_once() {
> > > > failed=0
> > > > + UPDATE_TARGET=$(readlink -f /system-update)
> > >
> > > This needs quotes in case the link target contains spaces.
> >
> > I think that's wrong. It only needs quoting when being used:
> >
> > $ cat test.sh
> > #!/bin/sh
> >
> > tmpdir=$(mktemp -d)
> >
> > touch "$tmpdir/file with spaces";
> >
> > FILE=$(ls $tmpdir)
> >
> > echo "$FILE"
> >
> > rm -rf $tmpdir
> >
> > $ bash test.sh | hexdump -C
> > 00000000 66 69 6c 65 20 77 69 74 68 09 73 70 61 63 65 73 |file
> > with.spaces|
> > 00000010 0a |.|
> > 00000011
> >
> > That being said, quotes don't hurt either.
>
> This is strange. I see the same thing, but the bash man-page says:
> "If the substitution appears within double quotes, word splitting and
> pathname expansion are not performed on the results."
> So I'd assume, that word splitting and pathname expansion are performed if
> no quotes are used, but that doesn't seem to happen.
They are, but only if these are applied in the current context. For
variable assignment we have:
A variable may be assigned to by a statement of the form
name=[value]
[...] All values undergo tilde expansion, parameter and variable
expansion, command substitution, arithmetic expansion, and quote
removal [...].
The quotes are indeed important if you do:
somecommand $(ls $tmpdir)
which in the setup of my script above would pass three arguments to
somecommand while
somecommand "$(ls $tmpdir)"
would only result in a single argument.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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