Is there a way to sort ps output by process start time, so newest are either at the top or bottom ?

On Linux ?

On SysV5 ?

On Mac ?

7 Answers 7


This should work on Linux and SysV5

ps -ef --sort=start_time
  • This works exactly as requested, thanks. After more digging I am not sure this is possible on Mac OS without a bit of awk
    – Dean Smith
    Jun 18, 2009 at 9:50
  • 1
    start_time worked. lstart did not. RHEL Mar 6, 2015 at 5:22
  • 1
    how to I reverse the order?
    – Phu Nguyen
    Sep 26, 2016 at 11:30
  • 2
    @PhuNguyen bit late to the party, but maybe someone else has a use for this. You can reverse the order by piping the output through tac.
    – Paul
    Oct 23, 2017 at 22:28
  • 1
    @Stephane try this: watch "ps -ef --sort=start_time | grep -v kworker | tail"
    – Sekenre
    Jul 25, 2019 at 10:37


$ ps aux --sort=lstart 


$ ps aux -O started
  • 3
    I'm afraid neither of those sorts by start time. It does display the start time, but doesn't sort.
    – Dean Smith
    Jun 18, 2009 at 9:45
  • 4
    The difference between lstart and start_time caught me out as well -- lstart gives a full timestamp, but cannot be used as a sort key. start_time gives the usual 'time within the last 24 hours, date otherwise' column, and can be used as a sort key. Both give 'STARTED' in the header.
    – LHMathies
    Apr 5, 2012 at 8:22
  • time within last hour: if a process was launched yesterday at a time later than today, it will appear after today's process ... can't be used by sort, unless a bit of "awk" changes that May 22, 2013 at 10:16
  • @OlivierDulac: not for me. 15/12 15:40 appears before 16/12 15:39, just as 13:39 appears before 15:38.
    – Gauthier
    Dec 16, 2014 at 14:41
  • 2
    lstart did not work for me. start_time did. Mar 6, 2015 at 5:21

Along with the great answers above, sometimes I just want to see the top 20 offenders by process sorted descending by time, cpu% and memory usage.

For that I use:

ps auxww --sort=lstart | sort -r -k3,4 | head -20

This would be on a CentOS platform, though I've enjoyed the same results on Fedora as well.

Oh and for grins, I sometimes want to remove a set of processes, so I simply use a variant on the above that includes a bit of grep -v action, such as:

ps auxww --sort=lstart | sort -r -k3,4 | grep -v "sbin/httpd" | head -20
  • --sort of ps does not work for me. Relying on shell sort. +1
    – kellogs
    Jan 25, 2015 at 11:32

I can't comment yet, but to answer the question about how to reverse the order of a time sort, just put a minus sign (-) in front of the field.
Example: ps -elf --sort=-start_time


Or try 'ls', as it allows time formats that are easy to sort, and easier to use.

( cd /proc; ls -td --full-time --time-style=+%s [0123456789]*; )

Outputs the date/time in epoch, newest procs at the top.

  • this only shows the pids
    – elig
    Aug 11, 2019 at 5:07

Try simple command:

ps | sort -k7 -n

-k7 for the time column and -n for numeric.



I know it's obsolete syntax, but I find it practical for brevity:

ps OT <other_options>

For example:

ps OT ax

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