iOS: Where is /proc/? Where is /proc/ in iOS? Or rather, why is it absent from the root directory structure?
It's typically a crucial interface to the kernel of any UNIX-like operating system; what else is in place to assume this role?
FYI: Following is the main system information and root directory structure of the device in question.


iPhone:~ mobile$ uname -a                       
Darwin Kernel Version 14.0.0: 
Wed Jun 24 00:46:37 PDT 2015;
root:xnu-2784.30.7~30
RELEASE_ARM_S5L8950X
iPhone5,2 N42AP                                         





iPhone:~ mobile$ find / -maxdepth 1
/
/.Trashes
/.file
/.fseventsd
/.ppuntether_inst
/Applications
/Developer
/Library
/System
/User
/bin
/boot
/cores
/dev
/etc
/lib
/mnt
/ppuntether
/private
/sbin
/tmp
/usr
/var
/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.