Hacking with listing local system locks

ABOUT lslocks lslocks lists information about all the currently held file locks in a Linux system. File locking is a mechanism that restricts access to a computer file by allowing only one user or process access at any specific time. Systems implement locking to prevent the classic interceding update scenario (see race condition). [bash] $lslocks …

Hacking with an arbitrary precision calculator

dc is a reverse-polish desk calculator which supports unlimited preci‐ sion arithmetic. It also allows you to define and call macros. Nor‐ mally dc reads from the standard input; if any command arguments are given to it, they are filenames, and dc reads and executes the contents of the files before reading from standard input. …