Listing all human users and number of their processes

Question

I am trying to list all of the real users via the command line along with a number of their processes, example:

root 73
user1 51
user2 68

I have tried several commands yet failed to get the output as written. These two are the ones I think should be the most appropriate for listing users only:

awk -F':' '{ if($3 >= 1000) print $1 }' /etc/passwd  

(does not list root since his PID is 0)

awk -F':' '$2 ~ "\$" {print $1}' /etc/shadow 

(requires root)

I am also aware that ps command is used for listing all processes, however my question is how to print specific number of processes per user after they are printed via command?

Not sure if piping is a solution, wc -l might help here for counting as well. Thanks.

Answer 1

pgrep can print the number of processes for a given user, and xargs uns a program for every line of its input. Put that together with your ´awk` command:

(echo root; awk -F: '{if($3>=1000)print $1}' /etc/passwd) | xargs -i sh -c 'echo "{} $(pgrep -cu {})"'

I'm adding root manually to the output of awk. One could use

if($3>=1000 || $3==0)

in the awk command instead.

Answer 2

Take advantage of the /proc filesystem: Your shell is bash, so:

shopt -s extglob
stat -c '%U %u' /proc/+([0-9])/ | awk '$2 >= 1000 {print $1}' | sort | uniq -c

Answer 3

There is a simpler approach that uses ps formating options and AWK

We know that by default, human users have UID that ranges from 1000 to 65533 ( UID 65534 is nobody user ).

We also know that ps has formatting flag -o , where we can choose to output UID as well as the process. The format would be the following ( note that I am showing here only 5 first lines )

ps -eo uid,cmd | head -n 5                                           
  UID CMD
    0 /sbin/init
    0 [kthreadd]
    0 [ksoftirqd/0]
    0 [kworker/0:0H]

Thus, we can do

ps -eo uid,cmd | awk '$1 >= 1000 && $1 < 65534 ' 

AWK helps us to print all lines where column 1, the UID is greater or equal to 1000 AND less than 635534.

Sample output from my system (where I have only one user ):

$ ps -eo uid,cmd | awk '$1 >= 1000 && $1 < 635534 ' | tail -n 5        
 1000 /usr/lib/at-spi2-core/at-spi2-registryd --use-gnome-session
 1000 /usr/lib/firefox/firefox google.com
 1000 ps -eo uid,cmd
 1000 awk $1 >= 1000 && $1 < 635534 
 1000 tail -n 5

---

EDIT

I've realized that OP wanted the number of processes used by human users.

If all you really care about is the number of processes that belong to human users, here's a quick solution:

ps --no-headers -eo uid,args --sort=uid | awk '$1 >= 1000 && $1 < 65534 {counter++}; END{print counter" human processes"}'

As for my previous solution, I've improved the AWK command, which uses associative arrays, based on UID, as well as added additional flags to ps command to include username and sort the output by UID.

 ps -eo uid,euser,cmd --sort=uid | awk '$1 >= 1000 && $1 < 65534 { HUMAN++; procTotals[$1]++; if( $1 > UID  ) username[$1]=$2; UID=$1  }  END{ print "Out of "NR" processes, "HUMAN" belong to human users";   for(i=1000;i<=UID;i++ )  print  username[i]":"procTotals[i] }'

Sample output:

xieerqi:$ ps -eo uid,euser,cmd --sort=uid | awk '$1 >= 1000 && $1 < 65534 { HUMAN++; >
Out of 215 processes, 88 belong to human users
xieerqi:84
testuser:4

For better readability , here's the formated code. Note that awk portion could be turned into a script with #!/usr/bin/awk -f shebang line

ps -eo uid,euser,cmd --sort=uid | awk '$1 >= 1000 && $1 < 65534 { 

HUMAN++; procTotals[$1]++; 
if( $1 > UID  ) username[$1]=$2; UID=$1  

}

END{ print "Out of "NR" processes, "HUMAN" belong to human users";   

for(i=1000;i<=UID;i++ )  
    print  username[i]":"procTotals[i] 

}'