Processes are designed to enable multiple programs to execute concurrently, increasing resource utilization and throughput of the system
Each process in 1.linux has a recognition number PID
2. The first boot process of the system is init,pid 1, the only process that runs directly from the system kernel, and the new processes are generated by system call Fork, except for Init, where each process has a parent process.
3 Each process has an actual user identification number (the user identification number that runs this process), the actual group identification number (the group identification number that runs this process).
4. The type of process, the interaction process, the process initiated by a shell.
A batch process that is not associated with a specific terminal and commits to a process that is sequentially executed in the waiting queue.
Daemon, after Linux starts, need to run the process in the background
5. The start of the process, manual start, scheduling start.
6. Process Management, PS view process,-a display all processes,-e, display the environment variables after the command,-U displays the username and start time information,-X shows the process with no control terminal,-f shows the process tree,-w wide row output,
7.kill, kill the process. The killall can also kill the process, and the KILL command specifies the process PID to kill, while killall specifies the termination signal for the process.
1. Job control refers to the behavior of the currently running process, also known as Process Control,
2.cmd & Background operation
Ctrl+d terminate a process at the front desk
CTRL + C terminates a process that is in the foreground (forced)
Ctrl+z to suspend a foreground process
Jobs shows background and is suspended process
BG restarts a pending task
FG puts a background running job in front of the operation.