• An inode (short for 'index node') is a data structure used by Linux to hold file information. Each inode in the Linux file system has a unique ID that identifies a single file or other item.
• On a Linux or Unix-like operating system, a PID stands for process identification number. When a process is created, it is automatically issued a PID. On a Unix-like system, a process is just a running instance of a programme, and each process has its own PID. Using the ps aux command and grep process name is the quickest technique to see if a process is running. Your process is running if you get output along with the process name/pid.

Read More: Explain file permission in Linux.