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processes

Identify CPU Memory Intensive Processes, Adjust process priority and id

kill processes

Objective

  • What key commands need to be memorized for this section?

ps

pgrep, basicall ps and gre but better formatted

  • -l flag for name
  • -u flag for user
  • -v flag for inverse of a user

pkill

  • Kills stuff by name
  • -t flag to kill a tty

What is a kill signal? kill -l for a list of all signals. Default is 15 SIGTERM. -9 -SIGKILL to kill it imediately. Checkpdf for more signals to memorize.

Kick out ssh user pkill -u USER sshd

Running stuff in the backgroud, pausing and starting again {#running-stuff-in-the-backgroud-pausing-and-starting-again id="54b8e3ad-5c1c-4379-b370-fbd579358991"}

(while true; do echo -n "My Program" >> ~/output.file; sleep 1; done) &

jobs

pausing a job kill -SIGSTOP %1

starting a job again kill -SIGCONT %1

ps axu Note the BSD syntax

  • Also look up AIX format in man page

Nice level is all abour priority

Niceness

  • Nice allows up to set a priority for a process.
  • Lower level higher priority
  • -20 most favoriable or 19 for least favoriable
  • Niceness is more a sugestion

  • df -h to see storage

    Create a 1 gig file

    dd if/dev/zip of=root/test.file bs=1M count=1024

    ps axo pid,comm,nice | grep httpd nice -n 0 httpd

    How to change nice on a running program

    renice -n 10 {Process ID}} renice -n 10 $(pgrep httpd) # $() is called a subshell time nice -n {19 or -20}} tar -cvf test.tar test.file

time followed by a command measures how long the command takes

upteime show how long server has been up

  • Calculate percentage of processing power
  • cat /proc/cpuinfo See how many CPU's you have
  • Proc shows info from kernel
  • (while true; do echo -n "My Program" >> ~/output.file; done) & for load testing
  • Calculate load
  • Get number of CPU's cat /proc/cpuinfo | grep "model name" | wc -l
  • What does -n do for echo?

Welcome to Top

  • Use keys l t and m
  • Can change niceness from here, press r then type PID
  • Press k to kill a process by PID
  • top -n, number of times to update and back to terminal
  • top -d, seconds between updates