Reverses lines of a file or files.

echo this is to be reversed | rev

returns:

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