How can I display the top results in my terminal in real time so that the list is sorted by memory usage?

  • 37
    On Linux, > and < move the sort column right and left. Since the %MEM column is just right of the %CPU column, which is also the default sort column, it takes only one keystroke to switch between the two. I know, your question has the macintosh tag, that's why I'm writing this answer as a comment. – Walter Tross Sep 19 '15 at 18:37
  • 10
    I prefer htop, mainly because it tells me how to do this. – lindhe Jan 19 '16 at 22:05

Use the top command in Linux/Unix:

  • press shift+m after running the top command
  • or you can interactively choose which column to sort on
    • press Shift+f to enter the interactive menu
    • press the up or down arrow until the %MEM choice is highlighted
    • press s to select %MEM choice
    • press enter to save your selection
    • press q to exit the interactive menu

Or specify the sort order on the command line

# on OS-X
top -o MEM
# other distros
top -o %MEM



  • 3
    On Linux it's top -o %MEM (note the "%") – Gabriel Hautclocq Sep 1 '17 at 9:19
  • @GabrielHautclocq It must depend upon your distribution of Linux, and the package bundled with it. Debian 7 uses procps-ng and there is no -o option at all in that version. SHIFT-M works for me once top is launched. – Christopher Schultz Sep 1 '17 at 13:59
  • top -o %MEM works on my debian 8 and 9, but not on debian 7, you are right @Christopher Schultz. – Gabriel Hautclocq Sep 3 '17 at 17:16
  • instead of <key>enter</key> it should be <key>q</key> – dashesy Jul 15 '19 at 19:23
  • "Press Shift + m" is a long-winded way of saying "type M". – Blaine Aug 9 '20 at 19:47

The command line option -o (o standing for "Override-sort-field") also works on my Xubuntu machine and according to the Mac man page of top it should work on a Macintosh too. If I want to short by memory usage I usually use

top -o %MEM

which sorts by the column %MEM. But I can use VIRT, RES or SHR too. On a Macintosh I would probably use mem or vsize.

I don't know why or how but this is pretty much different between Unix systems and even between Linux distributions. For example -o isn't even available on my Raspberry running Wheezy. It may be worth give it a try though.

  • 3
    The answer could user more clarity: %MEM is given as an answer to the eager reader; while it doesn't work everywhere (by far). – 7heo.tk May 6 '15 at 15:00
  • 1
    For Macbook 2014 this is saying: top -o %MEM invalid argument -o: %MEM – anon58192932 Jun 1 '15 at 17:43
  • I'm sorry to hear that. – ytg Jun 1 '15 at 20:03
  • This is the only answer that actually worked on centos for me. – Amalgovinus Mar 8 '16 at 22:40
  • 1
    @anon58192932 you should replace %MEM (or PID, VIRT, etc.) by any column name that you see when running top only. As noted by ytg, "on a Macintosh I would probably use mem or vsize". – ebosi Mar 29 '17 at 1:59

For Ubuntu 14.04 starting with


did the trick for me.

  • Works well for OSX as well. – ehime May 2 '16 at 18:16
  • 1
    it's different command. Looking for answer about the top command (as asked in this question) not htop. – Lukas Liesis Oct 28 '18 at 9:55

It seems like the -o flag will take the actual column name. So if the top command shows only "mem" then the command should be "top -o mem".

For the ubuntu machine I am testing with, the column is called "%MEM". On the OSX Yosemite I tried, it is "mem".


If top is already running, press o . Above the data, a prompt will appear:

primary key [xxxxx]:

Where xxxxx is the current sorting key. Type the name of the column by which you want to sort. If a column name contains "%" or "#", omit the character. For %CPU, just type "cpu".


The original question seems to have been for a Mac, but for anyone else stumbling across this answer, on Red Hat Linux (and many others), 'top -m' starts top with results sorted by memory usage.

  • Not on Debian 8 – marcovtwout Feb 27 '17 at 13:45
  • Worked on: Red Hat Enterprise Linux Server release 6.8 (none of the other answers worked). – Contango Mar 21 '17 at 17:18

On linux, run:

$ top

Then press, Shift + M.


Ubuntu 14.04 - this works just fine:

htop --sort-key=PERCENT_MEM
  • 4
    htop is not top – Anthon Aug 15 '16 at 9:28

If you're using the top that comes with Ubuntu (top -v = procps-ng version 3.3.10), then you can use these interactive keyboard shortcuts to change the sorting. Note that these are all capital letters, so either use shift or caps lock.


By default, they will be sorted in DESC order. Use R to toggle ASC/DESC.

To set the sorting from the command line option, use top -o %MEM. You can specify any column.

Not the answer you're looking for? Browse other questions tagged or ask your own question.