Recipe: Printing lines in reverse order

$ tac file

$ seq 5 | tac 
5 
4 
3 
2 
1

Print lines in reverse order using awk
======================================

$ seq 9 | \
awk '{ lifo[NR]=$0; lno=NR } 
END{ for(;lno>-1;lno--){ print lifo[lno]; } 
}'