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From: Robert Watson <rwatson@FreeBSD.org>
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To: Danny Braniss <danny@cs.huji.ac.il>
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Cc: freebsd-hackers@freebsd.org
Subject: Re: ps acting weird? 
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On Wed, 21 Jan 2009, Danny Braniss wrote:

> thanks Robert, it is always educational to read your answers!
>
> i have set kern.ps_arg_cache_limit, as you suggested to 4k, but i think 512 
> would have been enough (excluding those pathological cases of 'command *') 
> btw, this tomcat/java command line was 312 (why not use a config file!).
>
> which brings on another issue:
>
> ps -o command= -p 777
> /usr/local/diablo-jdk1.6.0/bin/java -Djava.endorsed.dirs= -classpath [...]
> while
> ps -o comm= -p 777
> java

ps distinguishes "comm", which is the binary name as stored in the process 
structure's p_comm field, and the command line, which is p_args.  From the 
ps(1) man page:

KEYWORDS
      The following is a complete list of the available keywords and their
      meanings.  Several of them have aliases (keywords which are synonyms).
...
      comm       command
      command    command and arguments

Robert N M Watson
Computer Laboratory
University of Cambridge