So the actual free memory on the system is free+buffers+cached. Linux only starts to use swap when all physical memory has been used. If more memory is needed for processes, it is released from the file system cache. Linux uses free physical memory for the file system cache to improve I/O performance. People often get a little confused about the memory information summary in the top part of the screen because the free memory listed seems very low to them. The "r" and "k" keys are used to renice and kill sessions. The sorting of the data can be altered using the following keys: To alter the order of the columns displayed, press the "o" key and use the upper case and lower case letters corresponding to each column to move then left and right of the "Current Fields" string. Toggle fields via field letter, type any other key to return When you are satisfied press the return key and you will see the displayed columns will have changed.Ĭurrent Fields: NAEHIOQTWKMbcdfgjplrsuvyzX for window 1:Def Capital letters mean the column is displayed. If you want to add or remove columns from the display, press the "f" key and toggle the letters in the "Current Fields" string. For the most part you can get away with just running top and looking at the output. The top command is probably the most well know utility for displaying the most resource intensive processes on the system. # omitting the grep line using a regular expression. # omitting the grep line using "grep -v". # Returns only those lines containing the string "ora", # Returns only those lines containing the string "ora". If there are a lot of processes on the system, you will probably want to page through or limit them using one of the filtering options, or the grep command. ![]() Ps axo stat,euid,ruid,tty,tpgid,sess,pgrp,ppid,pid,pcpu,comm Ps -eo pid,tid,class,rtprio,ni,pri,psr,pcpu,stat,wchan:14,comm To see every process with a user-defined format: ![]() To see every process running as root (real & effective ID) in user ![]() Ps -eo euser,ruser,suser,fuser,f,comm,label To see every process on the system using BSD syntax: To see every process on the system using standard syntax: The man page is very comprehensive, including the options to perform some useful common tasks. The ps command produces a report of the current processes on the system. Remember, the exams are hands-on, so it doesn't matter which method you use to achieve the result, so long as the end product is correct. This article introduces some of the commands and utilities used to manage processes on Linux, with specific reference to the information needed for the RHCSA EX200 and RHCE EX300 certification exams. Home » Articles » Linux » Here Linux Process Management (ps, top, renice, kill)
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |