iOS: Where is /proc/?
/proc is a pseudo-structure which is available on a lot of Unix systems but not on any version of OS X/macOS or iOS.

Kernel internals accessible through /proc are usually accessible by other means (either with some Terminal command or involving some ObjC/Swift coding) on Apple's iOS/watchOS/tvOS/macOS family of OS that all basically run on top of Next and then Apple's evolution of the Mach microkernel which is the XNU kernel.