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How to show top five CPU consuming processes with ps?

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6 Answers 6

up vote 10 down vote accepted

Why use ps when you can do it easily with the top command?

If you must use ps, try this:

ps aux | sort -kr 3,3 | head -n 6

If you want something that's truly 'top'esq with constant updates, use watch

watch "ps aux | sort -kr 3,3 | head -n 6"
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if u have to use ps, try with ps aux, and then pipe it with some way of sort or something. You will find the way. –  Boban P. May 28 '11 at 18:23
    
"You will find the way" isn't a particularly helpful answer :) –  Michael Mrozek May 28 '11 at 18:40
    
I agree :) will post solution with ps after the finale :) –  Boban P. May 28 '11 at 18:51
    
ps aux | sort -k 3,3 | tail -n 5 ;-) –  PlanasB May 28 '11 at 19:01
3  
sort -kr 3,3 gave me invalid count at start of 'r'. Had to change to sort -rk 3,3 (GNU sort 8.13) –  rzymek Dec 14 '13 at 19:51

Depending on your needs you may find this a little more readable:

ps -eo pcpu,pid,user,args | sort -k 1 -r | head -6

sample output:

%CPU   PID USER     COMMAND
 1.3     4 root     [ksoftirqd/0]
 1.1     9 root     [ksoftirqd/1]
 1.0 17606 nobody   /usr/sbin/gmetad
 1.0    13 root     [ksoftirqd/2]
 0.3 17401 nobody   /usr/sbin/gmond
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I don't think ps is what you are looking for. Have you looked at the output from top?

If you have GNU-Top, try using it's batch mode to spit out a process list sorted by cpu usage and using head/tail to get the top 5 lines (the first 8 are headers):

top -b -n 1 | head -n 12  | tail -n 5

The BSD top seems to behave differently and doesn't have a non-interactive mode, so use one of the other ps based solutions.

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In OS X, is top -o cpu -n 5 a way of achieving the same thing. Does anyone know? My top is different to your top. –  boehj May 29 '11 at 4:00
    
You're the one with the different top so you would be in a position to say. My top doesn't have -o and -n sets the number of times it refreshes the display before quitting. –  Caleb May 29 '11 at 5:28
    
Fair enough. I'll get on a Linux box this afternoon and take a look. My top doesn't seem to have a batch mode, which is quite limiting. There must be some way of piping top into other commands. I'll do some research. –  boehj May 29 '11 at 5:45
    
I mentioned the batch mode switch in my answer but it's actually unnecessary for my top because it auto-detects being part of a pipe instead of an interactive session. Did you try just piping it without that? –  Caleb May 29 '11 at 5:56
    
I can't figure it because if I do top -o cpu | head -n 12 | tail -n 5 the top process is started but it seems it's being run in the background as there's nothing printed in the terminal. –  boehj May 29 '11 at 6:22

The correct answer is:

ps --sort=-pcpu | head -n 6

So you can specify columns without interfering with sorting.

Ex:

ps -Ao user,uid,comm,pid,pcpu,tty --sort=-pcpu | head -n 6
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top on Mac OS X has a logging mode option in the form of top -l numberOfSamples (which seems to be the equivalent to the batch mode of GNU top). It is necessary, though, to have at least two samples because "the first sample displayed will have an invalid %CPU displayed for each process, as it is calculated using the delta between samples" (man 1 top).

# examples
top -o cpu -l 2 -n 5 | tail -n 6
top -o cpu -l 2 -n 5 -stats pid,command,cpu | tail -n 6
top -o cpu -l 2 -n 5 -stats pid,command,cpu -U $(logname) | tail -n 6
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Note that current versions of ps have sorting ability within them, based on field codes (given in the ps man page). The field code for processor usage is "c". You can use --sort c at the end of a ps command e.g. ps aux --sort c

This will put the process using the most cpu at the bottom of the list. Reverse order of the list by adding a minus to the field code used to sort e.g. ps aux --sort -c

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