yeboy

Named pipes
==========
mkfifo /tmp/pipe
echo Greetings > /tmp/pipe
cat /tmp/pipe

Shell pipes
==========
date | cat
ps aux | grep cron (vs pgrep)

Unix sockets
==========
- nc -lkU aSocket.sock
- More than two processes
- Bidirectional
- UID / GID credentials
- File descriptors
- Packet modes
- send() / recv() vs write / read()

SHM
==========
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>

void* create_shared_memory(size_t size) {
  // Our memory buffer will be readable and writable:
  int protection = PROT_READ | PROT_WRITE;

  // The buffer will be shared (meaning other processes can access it), but
  // anonymous (meaning third-party processes cannot obtain an address for it),
  // so only this process and its children will be able to use it:
  int visibility = MAP_SHARED | MAP_ANONYMOUS;

  // The remaining parameters to `mmap()` are not important for this use case,
  // but the manpage for `mmap` explains their purpose.
  return mmap(NULL, size, protection, visibility, -1, 0);
}

Memory- mapped files
==========
- Load a file in memory
- When a process does a read write it does in the file
- FD reference
- Faster?
- lsof | grep mem