Finding process count in Linux via command line

I was looking for the best way to find the number of running processes with 开发者_如何学Gothe same name via the command line in Linux. For example if I wanted to find the number of bash processes running and get "5". Currently I have a script that does a 'pidof ' and then does a count on the tokenized string. This works fine but I was wondering if there was a better way that can be done entirely via the command line. Thanks in advance for your help.

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On systems that have pgrep available, the -c option returns a count of the number of processes that match the given name

pgrep -c command_name

Note that this is a grep-style match, not an exact match, so e.g. pgrep sh will also match bash processes. If you want an exact match, also use the -x option.

If pgrep is not available, you can use ps and wc.

ps -C command_name --no-headers | wc -l

The -C option to ps takes command_name as an argument, and the program prints a table of information about processes whose executable name matches the given command name. This is an exact match, not grep-style. The --no-headers option suppresses the headers of the table, which are normally printed as the first line. With --no-headers, you get one line per process matched. Then wc -l counts and prints the number of lines in its input.

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result=`ps -Al | grep command-name | wc -l`
echo $result

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ps -Al | grep -c bash

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You can try :

ps -ef | grep -cw [p]rocess_name

OR

ps aux | grep -cw [p]rocess_name

For e.g.,:

ps -ef | grep -cw [i]nit

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Some of the above didn't work for me, but they helped me on my way to this.

ps aux | grep [j]ava -c

For newbies to Linux:

ps aux prints all the currently running processes, grep searches for all processes that match the word java, the [] brackets remove the process you just ran so it wont include that as a running process and finally the -c option stands for count.

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List all process names, sort and count

ps --no-headers -A -o comm | sort | uniq -c

You also can list process attached to a tty

ps --no-headers a -o comm | sort | uniq -c

You may filter with:

ps --no-headers -A -o comm | awk '{ list[$1] ++ } END { for (i in list) { if (list[i] > 10) printf ("%20s: %s\n", i, list[i]) } }'

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Following bash script can be run as a cron job and you can possibly get email if any process forks itself too much.

for i in `ps -A -o comm= --sort=+comm | uniq`; 
do 
    if (( `ps -C $i --no-headers | wc -l` > 10 )); then 
        echo `hostname` $i `ps -C $i --no-headers | wc -l` ;
    fi
done

Replace 10 with your number of concern.

TODO: "10" could be passed as command line parameter as well. Also, few system processes can be put into exception list.

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You can use ps(will show snapshot of processes) with wc(will count number of words, wc -l option will count lines i.e. newline characters). Which is very easy and simple to remember.

ps -e | grep processName | wc -l

This simple command will print number of processes running on current server. If you want to find the number of process running on current server for current user then use -U option of ps.

ps -U root | grep processName | wc -l

change root with username.

But as mentioned in lot of other answers you can also use ps -e | grep -c process_name which is more elegant way.

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ps aux | wc -l

This command shows number of processes running on the system by all the users.

For a specific user you can use the following command:

ps -u <username> | wc -l

replace with the actual username before running :)