42 Barcelona Project
Introduction signals: https://www.cs.kent.edu/~ruttan/sysprog/lectures/signals.html
UNIX signals: https://www.math.stonybrook.edu/~ccc/dfc/dfc/signals.html
signals: https://man7.org/linux/man-pages/man7/signal.7.html
SIGUSR1 y 2: https://www.gnu.org/software/libc/manual/html_node/Miscellaneous-Signals.html
What is SIGACTIONS: https://man7.org/linux/man-pages/man2/sigaction.2.html
Trabajr con Bits: bit wise operators https://www.geeksforgeeks.org/bitwise-operators-in-c-cpp