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

7ochem
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Theodor Coogan
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    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
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    I prefer htop, mainly because it tells me how to do this. – lindhe Jan 19 '16 at 22:05
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    If using htop, in addition to shift + M, you will likely want to turn off the display of threads and just show the main process memory consumption with shift + H. See https://unix.stackexchange.com/a/10403/27902. – Elijah Lynn May 11 '22 at 00:10

10 Answers10

664

Use the top command in Linux/Unix:

top
  • 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

References

https://stackoverflow.com/questions/4802481/how-to-see-top-processes-by-actual-memory-usage

Community
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Ramesh
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122

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.

ytg
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    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 06 '15 at 15:00
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    For Macbook 2014 this is saying: top -o %MEM invalid argument -o: %MEM – fIwJlxSzApHEZIl Jun 01 '15 at 17:43
  • I'm sorry to hear that. – ytg Jun 01 '15 at 20:03
  • This is the only answer that actually worked on centos for me. – Alkanshel Mar 08 '16 at 22:40
  • Works on Debian 8 – marcovtwout Feb 27 '17 at 13:46
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    @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 01:59
  • or cpu from mac's top -h: [-o <key>] [-O <secondaryKey>] keys: pid (default), command, cpu, cpu_me, cpu_others, csw, time, threads, ports, mregion, mem, rprvt, purg, vsize, vprvt, kprvt, kshrd, pgrp, ppid, state, uid, wq, faults, cow, user, msgsent, msgrecv, sysbsd, sysmach, pageins, boosts, instrs, cycles – alexey Feb 05 '18 at 19:53
  • +1 to the preceding comment. On my Mac (10.13.6), top -o '%CPU' did not work, notwithstanding that "%CPU" is how the column header appears. top -o CPU worked fine, as did top -o cpu. – AbuNassar Aug 21 '18 at 14:23
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    Yep, just do top -o MEM since "MEM" is on the list. – devinbost Jul 30 '21 at 18:37
  • use top -O to get a list of the field names which could be used for that -o argument – charlie arehart Jun 04 '22 at 17:30
  • top isn't a POSIX utility. Even POSIX utilities still only have a few standard options, but implementations will introduce their own extensions. Don't you see BSD find being vastly different from GNU find or busybox find? Depending on which userspace tool the distro uses you'll have different syntax – phuclv Aug 03 '22 at 05:41
25

For Ubuntu 14.04 starting with

htop -s PERCENT_MEM

or (equivalently)

htop --sort-key PERCENT_MEM

did the trick for me.

AdminBee
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Borjovsky
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15

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".

GlennTPeace
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8

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.

Anthony
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8

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.

M %MEM
N PID
P %CPU
T TIME+

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.

wisbucky
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7

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".

techraf
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George Boutin
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7

On linux, run:

$ top

Then press, Shift + M.

slm
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JBaczuk
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6

Ubuntu 14.04 - this works just fine:

htop --sort-key=PERCENT_MEM
don_crissti
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Коста Великов
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0

On RHEL 7 & 8, after running top I just type > to move across columns to sort by.

Since it starts sorted by CPU, only one > is required.

A commenter on the original question has also suggested this.

muru
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Alien Life Form
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