gargs

https://github.com/brentp/gargs

gargs is like xargs but it addresses the following limitations in xargs:

• it keeps the output serialized (in xargs the output one process may be interrupted mid-line by the output from another process) even when using multiple threads
• easy to specify multiple arguments with number blocks ({0}, {1}, ...) and {} indicates the entire line.
• easy to use multiple lines to fill command-template.
• easy to --retry each command if it fails (e.g. due to network or other intermittent error)

see also rush, mprocs. Seems to have inspired some work in this area, but isn't actively maintained.