I remember reading a book, Red Hat Linux System Administration Unleashed from 2000, where it has been postulated that knowing several tools with overlapping functionality is an essential skill, as you may end up on a broken or intentionally crippled system where, say, ls is unavailable, and you may need to cobble it together from shell and awk and what have you. Back then you could indeed run a risk of having /usr ni…
using echo * to find the right ld-linux filename and then the "executable" as an argument as the get out jail card in case you ran chmod -x -R /bin /usr/bin /usr/sbin for some reason.