rev — reverse lines of a file or files

echo this is to be reversed | rev

desrever eb ot si siht

rev .bash_profile

returns

eliforp_hsab. #

snoitcnuf dna sesaila eht teG #
neht ;] crhsab./~ f- [ fi
crhsab./~ .	
if

smargorp putrats dna tnemnorivne cificeps resU #

nib/EMOH$:HTAP$=HTAP

HTAP tropxe