What is process IDs (PIDs) in Linux?

In Linux, Process IDs (PIDs) are numerical identifiers assigned to each running process within the operating system. A process is an instance of a running program, which can perform tasks, execute code, and interact with system resources. PIDs serve as unique labels for these processes, allowing the operating system and users to differentiate between different running programs and manage them effectively.

Every process created by the Linux kernel is assigned a unique PID, which is an integer value greater than 1. The PID 1 is reserved for the init process, which is the first process started during system initialization and serves as the ancestor of all other processes. PIDs are assigned sequentially as new processes are created, and once a process terminates, its PID is freed up and can be reused for future processes. Apart from it by obtaining Linux Certification, you can advance your career as a Linux. With this course, you can demonstrate your expertise in Linux professional & help you to run applications, perform desired functions on your system and networks, create a network configuration, and maintain security administration, many more.

PIDs are crucial for process management in Linux. They enable the operating system to keep track of various aspects of processes, such as their state, resource usage, parent-child relationships, and execution status. For instance, PIDs are used to identify parent and child processes, allowing hierarchical relationships to be established. Additionally, PIDs enable the operating system to allocate system resources, such as memory and CPU time, to processes in a fair and controlled manner.

The ps command in Linux is commonly used to display information about running processes, including their PIDs, statuses, and resource usage. PIDs also play a crucial role in managing and controlling processes through signals. Signals are messages sent by the operating system or other processes to indicate events or request specific actions. By specifying the PID of a target process, users and administrators can send signals to control its behavior, such as terminating or suspending it.

In summary, Process IDs (PIDs) in Linux are unique numerical identifiers assigned to each running process within the operating system. These identifiers facilitate process management, resource allocation, and inter-process communication by allowing the system to differentiate and track individual processes. PIDs are essential for tasks such as identifying processes, managing process relationships, controlling execution, and monitoring system resource usage.