In Linux, how can I display memory usage of each process if I do a ps -ef? I would like to see the 'virtual memory', 'res memory', 'shared memory' of each progress. I can get that via top, but I want the same info in ps -ef so that I can pipe the output to grep with my process name.


Obtaining memory usage through ps is pretty unreliable. If you have a newer kernel it should support /proc/pid#/smaps which gives you some detailed information on each processes memory usage. Below is a pretty dirty and quick script to loop through each process that is open and grab the Size, Rss, Pss and Shared Clean/Dirty usage. Hopefully it can be useful in some kind of way.


for pid in $(ps -ef | awk '{print $2}'); do
    if [ -f /proc/$pid/smaps ]; then
            echo "* Mem usage for PID $pid"
            echo "-- Size:"
            cat /proc/$pid/smaps | grep -m 1 -e ^Size: | awk '{print $2}'
            echo "-- Rss:"
            cat /proc/$pid/smaps | grep -m 1 -e ^Rss: | awk '{print $2}'
            echo "-- Pss:"
            cat /proc/$pid/smaps | grep -m 1 -e ^Pss: | awk '{print $2}'
            echo "Shared Clean"
            cat /proc/$pid/smaps | grep -m 1 -e '^Shared_Clean:' | awk '{print $2}'
            echo "Shared Dirty"
            cat /proc/$pid/smaps | grep -m 1 -e '^Shared Dirty:' | awk '{print $2}'
  • 2
    You should be summing the Size column. See ezsmith's answer below. – Basil A Jan 10 '16 at 17:23
  • +1, evsmith's answer worked much better for me. – Jay Taylor Jan 8 '20 at 20:14

@user26528's answer doesn't quite calculate the memory correctly - you need the sum of the mappings in smaps, not just the top one. This script should do it:


for pid in $(ps -ef | awk '{print $2}'); do
    if [ -f /proc/$pid/smaps ]; then
        echo "* Mem usage for PID $pid"     
        rss=$(awk 'BEGIN {i=0} /^Rss/ {i = i + $2} END {print i}' /proc/$pid/smaps)
        pss=$(awk 'BEGIN {i=0} /^Pss/ {i = i + $2 + 0.5} END {print i}' /proc/$pid/smaps)
        sc=$(awk 'BEGIN {i=0} /^Shared_Clean/ {i = i + $2} END {print i}' /proc/$pid/smaps)            
        sd=$(awk 'BEGIN {i=0} /^Shared_Dirty/ {i = i + $2} END {print i}' /proc/$pid/smaps)
        pc=$(awk 'BEGIN {i=0} /^Private_Clean/ {i = i + $2} END {print i}' /proc/$pid/smaps)
        pd=$(awk 'BEGIN {i=0} /^Private_Dirty/ {i = i + $2} END {print i}' /proc/$pid/smaps)
        echo "-- Rss: $rss kB" 
        echo "-- Pss: $pss kB"
        echo "Shared Clean $sc kB"
        echo "Shared Dirty $sd kB"
        echo "Private $(($pd + $pc)) kB"
  • Outputs: line 16: + : syntax error: operand expected (error token is "+ ") which is the line that contains: echo "Private $(($pd + $pc)) kB", I'm running on CentOS 7. – Basil A Jan 10 '16 at 17:19
  • 2
    @evsmith why add 0.5 to Pss? – Pete Jun 23 '17 at 4:01
  • 1
    Running 10,000 small Awk scripts is a massive antipattern, you should just refactor all of this into a single Awk script. – tripleee Mar 2 '18 at 7:30
  • but this script itself consumes too much memory – mehmet riza oz Apr 10 '19 at 9:46

ps ef -o command,vsize,rss,%mem,size

I could not find an option for shared memory, but I did find options for % of total physical memory and the amount of swapspace that would be needed to swap out the process. This and much more is documented in the man page for ps.

  • Linux accounts shared memory in the memory for each process, which can lead to bogus sums if you have lots of processes attached to one largish shared memory segment. top, ps, and similar programs are all affected by this in the same way. – Peter Eisentraut Jan 29 '10 at 8:24
  • 1
    I know how shared memory works, but it appears ps cannot provide that information (or I was not able to find it in my ps documentation, at least). top or htop actually can show shared memory usage on a per process basis. – Justin Smith Jan 29 '10 at 13:52

List processes by memory usage

ps -e -orss=,args= | sort -b -k1,1n

  • 2
    Use ps -e -orss=,pid=,args= | sort -b -k1,1n to include the process id – Jay Feb 16 '14 at 22:45
  • ps can sort on its own: ps -eo rss=,args= --sort +rss – phil294 Jun 25 '19 at 23:49

you can use

top -n 1

I found that many times same process has fork sub process and you are interested in total memory used by the process. e.g. google chrome starts multiple process and you wish to know total memory taken by chrome. I found below one line command very useful

echo "%CPU   %MEM    MEM     PROCESS"
ps aux | awk '{mem[$11]+=int($6/1024)}; {cpuper[$11]+=$3};{memper[$11]+=$4}; END {for (i in mem) {print cpuper[i]"% ",memper[i]"% ",mem[i]" MB ",i}}' | sort -k3nr | head -n 5

It takes care of lots of things, like showing memory in MB, sorting on memory and mainly grouping by command. It is also grouping %CPU and %memory. It is showing data in user friendly format.

This command was inspired from this answer and it helped me lot to get idea on which process is taking up my resources.


List processes by mem usage

command : ps -e -orss=,args= | sort -b -k1,1n | pr -TW$COLUMNS\



The following one-liner also provides information on total memory consumption by the current user.

echo "------------------------------------" && mem=0 && while read -r rss comm ; do mbs=$((rss/1024)); mem=$((mbs + mem)); echo $mbs"MB - $comm"; done <<< "$(ps -u $USER -wo rss=,comm= --sort -rss)" && echo "------------------------------------" && echo $mem"MB: Memory used by user '$USER'"

I have just listed all user processes sorted by the highest memory usage in MB like this:

ps -u $USER -wo rss=,comm= --sort -rss | while read -r rss comm ; do echo $((rss/1024))"MB -" $comm; done

You can use command= instead of comm= to show the full path process.

The = just removes the column title.

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