After many years of administration of Unix/Linux systems and using bash for many tasks i’ve discovered the command tac, the contrary of cat,
What this command do it’s to concatenate and print files in reverse order, it writes each file to standard output, last line first.
bash$ cat file1.txt This is the line 1. This is the line 2. bash$ tac file1.txt This is the line 2. This is the line 1. |

