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I'm looking for somthing like top is to CPU usage. Is there a command line argument for top that does this? Currently, my memory is so full that even 'man top' fails with out of memory :)

Gilles 'SO- stop being evil'
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ripper234
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11 Answers11

145

From inside top you can try the following:

  • Press SHIFT+f
  • Press the Letter corresponding to %MEM
  • Press ENTER

You might also try:

$ ps -eo pmem,pcpu,vsize,pid,cmd | sort -k 1 -nr | head -5

This will give the top 5 processes by memory usage.

Steven D
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    Under Linux, simply press `M` to sort by physical memory usage (RES column). Under *BSD, run `top -o res` or `top -o size`. But [htop](http://unix.stackexchange.com/questions/4999/how-to-find-which-processes-are-taking-all-the-memory/5004#5004) is a lot nicer and doesn't even consume more memory than top (however it's not part of the basic toolset so you might not have it installed). – Gilles 'SO- stop being evil' Dec 19 '10 at 13:38
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    I had to press `s` to sort by `%MEM` and, then hit escape for top. – Bryce Guinta Jun 26 '16 at 20:40
  • Doesn't work on Solaris 9. – saulius2 Apr 30 '20 at 14:19
  • @Steven How can we group process with same parent? Basically firefox shows up in multiple times may be as it spawns multiple child processes. Is it possible to get combined memory usage? – Porcupine Mar 07 '21 at 21:45
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    `$ top` > `-bash: fork: Cannot allocate memory` - In case anyone else appreciates this – Curtis Yallop Oct 04 '21 at 22:39
14

If you have it installed I like htop once launching it you can press f6, down arrow (to MEM%), enter to sort by memory.

xenoterracide
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8

In Solaris the command you would need is:

prstat -a -s size

This will list all processes in order of descending process image size. Note that the latter is based on memory committed to the process by the OS, not its resident physical memory usage.

There are supposedly versions of "top" available for Solaris, but these are not part of the standard installation.

Joel Hoff
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7

Once top starts, press F to switch to the sort field screen. Choose one of the fields listed by pressing the key listed on the left; you probably want N for MEM%

Michael Mrozek
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6

This command will identify the top memory consuming processes:

ps -A --sort -rss -o pid,pmem:40,cmd:500 | head -n 6 | tr -s " " ";z"
Ouki
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user90191
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  • Doesn't work on Solaris 9: `ps: illegal option -- - ps: ort is an invalid non-numeric argument for -s option ps: illegal option -- r ps: s is an invalid non-numeric argument for -s option ps: unknown output format: -o pmem:40 ps: unknown output format: -o cmd:500` – saulius2 Apr 30 '20 at 14:22
5

One nice alternative to top is htop. Check it, it is much more user friendly than regular top.

Klark
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It can be achieved in multiple ways, My favourite one is:

The PS way:

  1. [arif@arif ~]$ ps -eo pid,cmd,%cpu,%mem --sort=-%mem

    Where,

    • -e: to select all process
    • -o: to apply to the output format
    • pid,cmd,%cpu,%mem: Output format in exact order. Here, pcpu and pmem can be used instead of %cpu and %mem.
    • But sadly (don't know why) it doesn't work on some machine (Oracle Linux) and some older machine. You can use the following similar alternatives.

  2. [arif@arif ~]$ ps aux --sort '-%mem' --cols 120 | head

    Where,

    • --cols 100: to specify column width of the output as sometimes cmd gets very long. This is not necessary if you don't want curtailed commands with arguments.
    • aux: to see every process on the system using BSD syntax

  3. [arif@arif ~]$ ps -eo pid,cmd,%cpu,%mem --sort -rss

    Where,

    • -rss: resident set size, the non-swapped physical memory that a task has used

  4. [arif@arif ~]$ ps aux --sort -rss --cols 120

The top way:

[arif@arif ~]$ top -b -o +%MEM

Where,

  • -b: to use top as batch mode.
  • -o: to override sort fieldname followed by a fieldname %MEM

And you can always use head and/or tail to control the output.

arif
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  • Doesn't work on Solaris 9. The `top` cmd-lines gives: `top: '+%MEM' is not a recognized sorting order. Try one of these: cpu size res time ` – saulius2 Apr 30 '20 at 14:25
2

Globally: It's always recommended to use a log analyser tool for logging history logs such as Splunk, ELK etc. So that using query language you can easily get the PIDs and its usage by CPU & memory.

AT SERVER/OS LEVEL: From inside top you can try the following:

 Press SHIFT+M  ---> This will give you a process which takes more memory in descending order.

You might also try:

$ ps -eo pid,ppid,cmd,%mem,%cpu --sort=-%mem | head -10

This will give the top 10 processes by memory usage. Also you can use vmstat utility to find the RAM usage at same time not for history.

Santosh Garole
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0

You can try ps aux --sort -rss | head or ps aux | sort -nk +4 | tail

David Okwii
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0

This alias works nice for me in a bash shell:

alias mtop='{ echo "Mem% PID Binary"; ps -A --sort -rss -o pid,pmem:40,cmd:500 | tail -n +2 | head -n 10 | tr -s " " | sed -r "s/^\s*([0-9]+) ([0-9.]+) ([a-zA-Z/]+).*$/\2 \1 \3/"; } | column -t -s " "'

This will print out a neat list of processes sorted by memory consumption:

-=# mtop
Mem%  PID     Binary
22.9  528235  /opt/intellij
5.4   906569  /usr/share/elasticsearch/jdk/bin/java
3.7   544512  /usr/bin/node
2.2   986170  /usr/lib/firefox/firefox
1.9   795138  /usr/bin/node
1.1   795188  /usr/bin/node
1.0   747819  /usr/lib/jvm/java
0.9   599     /usr/bin/pipewire
0.7   414     /usr/lib/Xorg
0.7   544536  /usr/bin/node
fasseg
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0

On macOS, ps does not support the --sort option.

You can use the BSD-only -m flag to sort by "memory usage," which avoids piping all rows through sort. (The ps man page doesn't specify exactly which "memory usage" metric is used.)

ps -m -aexo pmem,rss,vsize,pid,etime,user,args | head

Or, if you want sorting by CPU: you can use the BSD-only -r flag to sort by cpu usage.

ps -r -aexo pcpu,cputime,pid,etime,user,args | head
Carl Walsh
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