Re: [PATCH 2/2] copy-firmware: fail gracefully if moreutils parallel is installed

[Maxim Cournoyer <maxim.cournoyer@gmail.com>]

Hi again,

Timur Tabi <ttabi@nvidia.com> writes:

[...]

>  has_gnu_parallel() {
>      if command -v parallel > /dev/null; then
> +        # The moreutils package comes with a simpler version of "parallel"
> +        # that does not support the --version or -a options.  Check for
> +        # that first.  In some distros, installing the "parallel" package
> +        # will replace the moreutils version with the GNU version.
> +        parallel --version >/dev/null 2>&1
> +        if [ $? -ne 0 ]; then
> +            return 1
> +        fi

I just rechecked; I don't think this currently work, it'd require
complicating the script to accommodate this less featureful parallel
variant, which is why I had opted to use GNU Parallel in the first place
:-).

If you inspect how parallel is used, it is passed a list of commands
from a file, which GNU parallel accepts via its '-a' option:

--8<---------------cut here---------------start------------->8---
    parallel -j"$num_jobs" -a "$parallel_args_file"
--8<---------------cut here---------------end--------------->8---

Moreutils' parallel lacks the '-a' option, and doesn't appear to offer
something equivalent.  So instead of simply adding appending your
command lines to a file, you'd have to build a space-separated list of
quoted commands... which makes quoting annoying and complicates
debugging (in the former case you can just inspect/execute the commands
file).

-- 
Thanks,
Maxim