Re: [Qemu-devel] [PATCH v2 1/3] qemu-iotests: Modern shellscripting(use $() instead of ``)

[Eric Blake]

[adding Jeff]

On 10/18/18 2:14 AM, maozy wrote:
> Hi, Eric
>
> On 10/18/18 11:28 AM, Eric Blake wrote:
> > On 10/17/18 10:17 PM, Mao Zhongyi wrote:
> > > Various shell files contain a mix between obsolete ``
> > > and modern $(); It would be nice to convert to using $()
> > > everywhere.
> > >
> > > `pwd` and `basename $0` are in 231 files under directory
> > > tests/qemu-iotests, so replaced it with the following:
> > >
> > > sed -i 's/`pwd`/$(pwd)/g' $(git grep -l "\`pwd\`")
> >
> > No. Instead, I'd rather a separate patch that does:
> >
> > s/`pwd`/$PWD/
> > s/\$(pwd)/$PWD/
> >
> > since POSIX requires $PWD to be sane, and thus save us a wasted forked 
> > process.
>
> I got you, thank you very much.

> > At one point, someone (Jeff?) proposed a cleanup patch that got rid of 
> > a lot of cruft in iotests, including the fact that scripts that don't 
> > use $seq don't need to assign seq=$(basename $0).  We should probably 
> > revive that rather than just making pointless churn on stuff that is 
> > garbage anyways.  But I don't have time to look up a URL to that older 
> > series at the moment.
>
>
> I think I might have found this patchset, but it was a long time ago.
>
> https://lists.gnu.org/archive/html/qemu-devel/2017-10/msg04056.html

Yes, you found it.

> I will remove this patch from this series and resend a separate patch
> to replace `pwd` and "$(pwd)" with $PWD. Am I right?

That whole series from Jeff should be revived and rebased to master.  I 
don't know if Jeff has time to commit to it any more, so anyone is 
welcome to pick it up at this point.  But your plan in the meantime 
sounds reasonable.

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org