Linux Labs

Users, permissions, and processes / Stage 10 of 13

Observing processes

Not running Starting usually ~20 s
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Step 1 of 7 · on a machine · 4 min

The site is slow

What you will learn

  • Find processes by name and by CPU load.
  • Read a process row in ps — number, parent, owner, and command line.
  • Tell a running, a sleeping, and a stopped process apart by their state.

Users complain that the site on this server responds slowly. You have not started anything on the machine yourself. Find out what keeps the CPU busy.

Exercise · look

What keeps the CPU busy

Run top: it shows the running processes and refreshes the list every three seconds. Look at the summary above the list and at the top row of the list, then quit with q.

First, predict

You started nothing. How many processes will top count in the Tasks line?

Now start the exercise, run the command and compare your prediction with the output.

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Check yourself 1 question

Which user does the indexer that keeps the CPU busy run as?

  • student is on the top row for top itself, which you started. The indexer row shows another name under USER.

  • Many processes run as root, but not all of them. Look at the USER column on the indexer row.

  • Every process has an account, even one started without you. The USER column shows it.

The USER column on the indexer row says www-data.

Ubuntu 24.04
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