tac --helptac --versiontac filenametac abc.txttac file1 file2 ...tac abc.txt def.txttac -b abc.txt def.txttac -r abc.txt def.txtecho "Sandy,Mandy" | tac echo "Sandy,Mandy" | tac -s ,echo "Sandy,Mandy" | tac -b -s ,Sharing is Caring