Process: Process status: 1. Process-related process related to the terminal 2. Process-related process related to the terminal Process status Parent-child relationship Priority relationship pid, 0-139, the smaller the number, the higher the priority, 0-99 : Kernel-adjusted 100-139 users can control the tracking process: process number: pid Each process has a parent process, except for the init process, which is the father of the process. The process number is 1, ps processstate sysv style: - BSD style: Without - aux a: All processes related to the terminal x: Processes unrelated to the terminal u: Process status: D: Unstoppable sleep R: Run or ready S: Interruptible sleep T: Stop Z: Zombie process < High priority process N Low priority process + Process in the foreground process group Frontend: Terminal related l Multithreaded process s Session process link -els pstree: Shows the process tree in the current system pgrep :pgrep -u root bash Specifies the user and process Name shows the process number pidof: Find the pid number based on the user name top: cpu load : us: user space user process percentage sy: system space occupied percentage ni: nice value id: CPu idle percentage wa; waiting for I/o completed time hi: hardware interrupt completed time SI: soft interrupt occupied time St : time stolen PR: indicates priority VIRT: virtual priority RES: resident priority SHR: shared memory size M: occupied memory case sorting P: sorted by occupied CPU case T: by occupancy time Sort l: Whether to display the average load and start time t: Whether to display the information related to the CPU status m: Whether to display the memory related information c: Whether to display the complete command line information q: Exit top k: Terminate a process -d refresh time -b press the screen refresh, in batch mode Local internal process communication: (IPC: inter process COmmunication) Shared memory Signal: singal semaphore: semaphore signal kill -l display signal 1, SIGHUP allows a process to reread without restarting Its configuration file and let the new configuration information take effect 2, SIGINT terminates a foreground process 9, SIGKILL kills Process 15, SIGTERM terminates a process Specify a signal: Credit number: kill -l Signal name: kill -SIGKILL Signal name shorthand: kill -KILL kill pid killall command As long as the process name will be killed Adjust the process's nice (priority Level) Adjust the nice value of the process that has been started: reniceNIPID Specify the nice value at startup: nice -n ni command vmstat system status view command free kill pkill foreground: occupies the command prompt background: after startup, release the command prompt, follow-up The operation is done in the background. Front--> Background: ctrl +z: Send the job in the foreground to the background command +& Let the command execute in the background bg: Let the background stop the job continue to run jobs: View all the jobs in the background No.: The default next operation with + The command with - will be the second operation bg + job number fg : Recall the process back to the foreground, fg [JOBID] /proc/meminfo View memory and CPU related information