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[Intro Music]

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Let me now briefly summarize what

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we did during previous few

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lectures. First we have used

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apt-get utility in order to

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install missing htop package. This

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package is missing in this Ubuntu

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image that we are running using

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Docker. We have actually used the apt-

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get before in order to install other

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package called 'mandb' in order to

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get the man pages working in Linux

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computer. I have also shown you how

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to run htop utility, and how to get

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information about the currently

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running processes. You could also

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perform other actions with those

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processes like kill processes and

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filter them if you want. Also

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using htop utility, you could

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observe how much CPU and memory are

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currently used by all running

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processes. And I see that CPU

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consumption is around 2%, and

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memory consumption is around 300

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megabytes. Also, I see here limit

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2.92 gigabytes. And actually

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it is a limit of Docker Host. I

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could go to Docker Settings and

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quickly demonstrate it. Go to

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Dashboard, click on Settings icon,

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go to Resources, and here is this

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memory limit, 3 gigabytes. And

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here is also Swap size, 1

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gigabyte. And you actually see this

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limit here in this table as well.

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It means that this Docker container

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is able to utilize up to three

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gigabytes of RAM and up to one

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gigabyte of swap size. Great. But

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the main idea why I wanted to show

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you this htop utility is that it

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actually shows out of the box

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command that was used for start of

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corresponding process. Actually,

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you could use additional option

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along with 'ps' command. Let me show

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you this quickly; 'ps -f';

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and with this option, you could

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also see command that was used for

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start of corresponding process. For

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example, I have just entered 'ps

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-f' command, that's why here in

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this list, I see 'ps' along with

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'-f' option. Great. That is how you

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could use ps, top and htop utility.

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Now let me do for you quick demo

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and run htop utility on another

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Ubuntu computer that has much more

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processes than this container. Let

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me switch there, and enter 'htop'

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here. It is available here out of

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the box. And here's a long list of

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different processes. And you may

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see that some of processes were

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started by root user and some by

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bogdan user. Actually, you could

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run htop utility along with option

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that will filter processes by user.

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Let me quickly show you that, 'htop

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--help'; and here you will

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see this option '-u', it is

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short version of this option, or

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long version is '--user'. And

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if you use this option, you need to

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supply mandatory argument for this

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option. Recap that we have talked

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about arguments for options before.

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And for example, if I want to list

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only my processes, I could use this

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option, 'htop -u'; and if I

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use short version of option, I need

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to supply argument for option after

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space like so, '-u ', and

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type my name. And now I see only my

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processes here in this table. Let

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me exit from here. And let's list

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all processes that were started by

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root user; and let me use long

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version of this option, '--user';

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and in such case, I need

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to use here equal sign and type

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name of the user 'root', like so, press

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Enter, and now I see processes that

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were started only by 'root' user. All

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right, let me exit from here. And

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let me start htop without any

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additional options like this. And

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let me show you how you could

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perform for example, filtering of

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processes. For that you could press

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F4; and let's filter for

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example by 'bash'; and now I will

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find 'bash' process that was started

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by 'bogdan' user. Also let's

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filter for example by 'gnome', like

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so. And now I will see all

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processes that have 'gnome'

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somewhere in the process name.

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Alright, that's how you could filter

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processes. Now let me

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demonstrate to you how to sort

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processes. For that you

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could use F6. Let me press it. And

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here in the left section, you could

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sort for example by PERCENT_MEM;

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and now I see that all processes

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were sorted by percentage of memory

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usage. And here is the process that

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utilizes around 6% of memory. It is

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actually this graphical user

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interface desktop I am currently

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working in, nautilus-desktop. Okay.

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Also you see limits of this

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computer. And now one gigabyte of

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RAM is utilized and the maximum

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size is two gigabytes. And actually

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I'm running this Ubuntu computer as

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virtual machine using VMware Fusion,

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and I have set the limit of two

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gigabytes of RAM for this computer.

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That's why here I see this limit,

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two gigabytes. Alright, that's all

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for this demonstration. And please

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note that if you don't have

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separate Ubuntu computer, no

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worries, you are still good to go

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just with Linux container running

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using Docker. That's all for those

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lectures about processes. I hope

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you enjoyed them. And next let me

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talk about the standard in - stdin, standard

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out - stdout, and standard error - stderr of every

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process. You'll understand those

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three different data flows of every

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process, and you'll understand how

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to use them. I will see you guys in

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the next lecture. Bye-Bye.

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[no audio]