On Sat, 15 May 2010, Denys Vlasenko wrote:
> On Friday 14 May 2010 21:44, Cristian Ionescu-Idbohrn wrote:
> > On Fri, 14 May 2010, Denys Vlasenko wrote:
> >
> > > I did discover a lot of interesting details about shells
> > > while hacking on them. One is that bare "read"
> > > is NOT the same thing as "read REPLY"! Look at this:
> > >
> > > $ echo " foo b\ar " | { read -r; echo "[$REPLY]"; }
> > > [ foo b\ar ]
> >
> > $ dash -c 'echo " foo b\ar " | { read -r; echo "[$REPLY]"; }'
> > read: 1: arg count
> > []
>
> They are not bash compat :)
Pick any one shell as _the_ reference shell and compare it with all other
major shells. The in"compat"ibilities (bash or not bash) will be
noticable.
> > > $ echo " foo b\ar " | { read -r REPLY; echo "[$REPLY]"; }
> > > [foo b\ar]
> >
> > $ dash -c 'echo " foo b\ar " | { read -r REPLY; echo "[$REPLY]"; }'
> > [foo br]
> >
> > (with a bell ringing)
>
> Bug per http://www.opengroup.org/onlinepubs/009695399/utilities/read.html
Yes. And there's still a lot of room for interpretation:
-r
Do not treat a backslash character in any special way. Consider each
backslash to be part of the input line.
But what is an input line?
Is this an input line?
bash$ read -r REPLY <<EOF
> foo b\ar
> EOF
bash$ echo "[$REPLY]"
[foo b\ar]
Is this an input line too?
bash$ echo " foo b\ar " | { read REPLY; echo "[$REPLY]"; }
[foo bar]
Busybox ash imitating bash:
ash$ read -r REPLY <<EOF
> foo b\ar
> EOF
ash$ echo "[$REPLY]"
[foo b\ar]
ash$ echo " foo b\ar " | { read REPLY; echo "[$REPLY]"; }
[foo bar]
What about this?
dash$ read -r REPLY <<EOF
> foo b\ar
> EOF
dash$ echo "[$REPLY]"
[foo br]
dash$ echo " foo b\ar " | { read REPLY; echo "[$REPLY]"; }
[foo br]
(rings the bell in both cases)
But I thought we were discussing the bash REPLY obfuscatin, did we not?
Cheers,
--
Cristian
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