Core detection is not tested very well on SPARC: I do not have access to a T4-2, so I rely on users to provide improvements. Feel free to do so.

Point taken on the double-quotes. Thanks.

I noticed on SPARC T4-2 parallel launches 16 threads with or without the –use-cpus-instead-of-cores. I would have expected 128 – the number of vcores.

Being the author of GNU Parallel I see myself as a more authoritative source than admin-magazine. GNU Parallel _used_ to default to 9 processes. It was changed in 20110122 after a user vote.

While it is good practice to enclose VARIABLES in double quotes, that is not the case with {} (which is not a variable but a replacement string).

GNU Parallel deals with the spacing, so putting ” around is always unneeded and can cause harm in some situations. Here for example: parallel echo ‘a “{}”‘ ::: ‘a b’

GNU parallel defaults to 9 threads if -j is not specified. See here: http://www.admin-magazine.com/HPC/Articles/GNU-Parallel-Multicore-at-the-Command-Line-with-GNU-Parallel

An alternative is to specify “-j +0”, allowing parallel to automatically determine the number of core. However, this doesn’t always work on Linux and never works on SPARC Solaris.

It is a good practice to enclose variables in double quotes, thus saving yourself a lot of trouble when the variable’s value happens to contain a space or a special character.