Break stdin into ~1M blocks, feed each block to stdin of new command

Run commands on multiple CPU cores.
More information: <https://www.gnu.org/software/parallel>.
Trick copyright: tl;dr; <https://github.com/tldr-pages/tldr>

cat {{big_file.txt}} | parallel --pipe --block 1M {{command}}

click the source code to copy install parallel on any operating system with command-not-found.com