These are good suggestions, but maybe it’s worth noting that one of the solutions offered in the article is not equivalent: tail -f /some/log/file | grep -E

These are good suggestions, but maybe it’s worth noting that one of the solutions offered in the article is not equivalent: tail -f /some/log/file | grep -E 'thing1.*thing2' This will only match if the subpatterns, i.e. thing1 & thing2, are in this order, and also require that the patterns do not overlap.