MySQL Foreign Key Constraint Failure

When deleting a row from a table, MySQL might give a foreign key constraint failure. To find out what is the problem one can execute the following command:

SHOW INNODB STATUS;

Useful UNIX Commands

I will continuously update this posting with useful UNIX commands.

"tac" - reverses a list or a file.
"strace" - traces system calls of a process. Example: "strace -t -T -v -o OUTPUT java".