command: tac
usage: concatenate and print files in reverse
syntax: $ tac [OPTION]... [FILE]...
examples:
1. To print options and help of this command
$ tac --help
2. To print the file in reverse order with the last line first
$ cat test.txt
1 this line one
2 this line two
3 this line three
4 this line four
5 this line five
$ tac test.txt
5 this line five
4 this line four
3 this line three
2 this line two
1 this line one
regards,
dhanasekar