Linux Proc directory

/proc is not a usual file system,  kernal put the info about active process in /proc.   it contains the PID as dir name for the processes running in the OS, and the info for memory, cmd etc is saved in the directory.   It used by top , htop to prase the info . 

Some of the files are binary file. 

cmd : what command is running 

environ: environment variable. 

cwd: link where the process is running