Discovering System Processes
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Note that the default ps will only show your processes; to view all the user processes running on your computer, use the a switch:
ps -aPID TT STAT TIME COMMAND 2100 v0 Ss 0:00.18 -csh (csh) 2403 v0 R+ 0:00.00 ps -a 313 v1 Is+ 0:00.13 -csh (csh) 314 v2 Is+ 0:00.25 -csh (csh) 315 v3 Is+ 0:00.12 -csh (csh) 316 v4 Is+ 0:00.01 /usr/libexec/getty Pc ttyv4 317 v5 Is+ 0:00.01 /usr/libexec/getty Pc ttyv5 318 v6 Is+ 0:00.01 /usr/libexec/getty Pc ttyv6 319 v7 Is+ 0:00.01 /usr/libexec/getty Pc ttyv7
You may find it more useful to see which users started which commands; to
do this, include the u switch:
ps -auUSER PID %CPU %MEM VSZ RSS TT STAT STARTED TIME COMMAND genisis 2404 0.0 0.2 428 244 v0 R+ 12:26PM 0:00.00 ps -au root 273 0.0 0.4 620 448 con- I+ 4:53PM 0:00.02 /bin/sh /usr/loc root 292 0.0 0.4 624 452 con- I+ 4:53PM 0:00.01 /bin/sh /usr/loc genisis 313 0.0 0.8 1328 944 v1 Is+ 4:53PM 0:00.13 -csh (csh) genisis 314 0.0 0.8 1336 960 v2 Is+ 4:53PM 0:00.25 -csh (csh) genisis 315 0.0 0.8 1328 944 v3 Is+ 4:53PM 0:00.12 -csh (csh) root 316 0.0 0.5 920 628 v4 Is+ 4:53PM 0:00.01 /usr/libexec/get root 317 0.0 0.5 920 628 v5 Is+ 4:53PM 0:00.01 /usr/libexec/get root 318 0.0 0.5 920 628 v6 Is+ 4:53PM 0:00.01 /usr/libexec/get root 319 0.0 0.5 920 628 v7 Is+ 4:53PM 0:00.01 /usr/libexec/get genisis 2100 0.0 0.8 1336 960 v0 Ss 9:46AM 0:00.19 -csh (csh)
I find the output easier to read if I include the c switch as it will only show the name of the command, instead of the path:
ps -aucUSER PID %CPU %MEM VSZ RSS TT STAT STARTED TIME COMMAND genisis 2414 0.0 0.2 428 244 v0 R+ 12:31PM 0:00.00 ps root 273 0.0 0.4 620 448 con- I+ 4:53PM 0:00.02 sh root 292 0.0 0.4 624 452 con- I+ 4:53PM 0:00.01 sh genisis 313 0.0 0.8 1328 944 v1 Is+ 4:53PM 0:00.13 csh genisis 314 0.0 0.8 1336 960 v2 Ss+ 4:53PM 0:00.26 csh genisis 315 0.0 0.8 1328 944 v3 Is+ 4:53PM 0:00.12 csh root 316 0.0 0.5 920 628 v4 Is+ 4:53PM 0:00.01 getty root 317 0.0 0.5 920 628 v5 Is+ 4:53PM 0:00.01 getty root 318 0.0 0.5 920 628 v6 Is+ 4:53PM 0:00.01 getty root 319 0.0 0.5 920 628 v7 Is+ 4:53PM 0:00.01 getty genisis 2100 0.0 0.8 1336 960 v0 Ss 9:46AM 0:00.21 csh
We're still not seeing all of the processes on this system, though. To do this, include the x switch to display the running daemons; this will be a longer output, so we'll pipe it to the more utility:
ps -aucx |moreUSER PID %CPU %MEM VSZ RSS TT STAT STARTED TIME COMMAND genisis 2417 0.0 0.2 428 244 v0 R+ 12:32PM 0:00.00 ps root 1 0.0 0.2 532 304 ?? ILs Sat11AM 0:00.06 init root 2 0.0 0.0 0 0 ?? DL Sat11AM 0:00.11 pagedaemon root 3 0.0 0.0 0 0 ?? DL Sat11AM 0:00.00 vmdaemon root 4 0.0 0.0 0 0 ?? DL Sat11AM 0:00.20 bufdaemon root 5 0.0 0.0 0 0 ?? DL Sat11AM 0:09.53 syncer root 27 0.0 2.0 70780 2540 ?? ILs Sat11AM 0:00.08 mount_mfs root 30 0.0 0.1 208 92 ?? Is Sat11AM 0:00.00 adjkerntz root 110 0.0 0.3 536 368 ?? Is 4:53PM 0:00.03 dhclient root 163 0.0 0.5 904 608 ?? Ss 4:53PM 0:00.53 syslogd daemon 166 0.0 0.4 916 556 ?? Is 4:53PM 0:00.01 portmap root 181 0.0 0.5 263052 576 ?? Is 4:53PM 0:00.00 rpc.statd root 197 0.0 0.6 1028 764 ?? Is 4:53PM 0:00.02 inetd root 199 0.0 0.6 956 700 ?? Is 4:53PM 0:00.64 cron root 202 0.0 1.0 1424 1216 ?? Is 4:53PM 0:00.66 sendmail root 227 0.0 0.4 876 488 ?? Is 4:53PM 0:00.34 moused root 273 0.0 0.4 620 448 con- I+ 4:53PM 0:00.02 sh root 292 0.0 0.4 624 452 con- I+ 4:53PM 0:00.01 sh genisis 313 0.0 0.8 1328 944 v1 Is+ 4:53PM 0:00.13 csh genisis 314 0.0 0.8 1336 960 v2 Ss+ 4:53PM 0:00.26 csh genisis 315 0.0 0.8 1328 944 v3 Is+ 4:53PM 0:00.12 csh root 316 0.0 0.5 920 628 v4 Is+ 4:53PM 0:00.01 getty root 317 0.0 0.5 920 628 v5 Is+ 4:53PM 0:00.01 getty root 318 0.0 0.5 920 628 v6 Is+ 4:53PM 0:00.01 getty root 319 0.0 0.5 920 628 v7 Is+ 4:53PM 0:00.01 getty genisis 2100 0.0 0.8 1336 960 v0 Ss 9:46AM 0:00.21 csh root 2239 0.0 3.6 5012 4512 ?? Ss 10:57AM 0:00.40 perl root 2240 0.0 3.6 5012 4512 ?? I 10:57AM 0:00.02 perl root 0 0.0 0.0 0 0 ?? DLs Sat11AM 0:00.06 swapper
Wow, no wonder the kernel needs to assign PIDs to keep track of what is happening on your FreeBSD system. If you find it hard to remember which column is which, add an h to your switches to force ps to rewrite the column headings on every screen.
You may have noticed that our columns changed when we introduced the u switch; the most notable new columns are %CPU and %MEM. Sometimes you may find it more useful for ps to display the processes by CPU or memory usage, rather than in numerical order. To sort by memory usage, use the m switch; to sort by CPU usage, use the r switch.
ps -mPID TT STAT TIME COMMAND 314 v2 Ss+ 0:00.28 -csh (csh) 2100 v0 Ss 0:00.27 -csh (csh) 313 v1 Is+ 0:00.14 -csh (csh) 315 v3 Is+ 0:00.12 -csh (csh) 2570 v0 R+ 0:00.00 ps -m
ps -rPID TT STAT TIME COMMAND 313 v1 Is+ 0:00.14 -csh (csh) 314 v2 Ss+ 0:00.28 -csh (csh) 315 v3 Is+ 0:00.12 -csh (csh) 2100 v0 Ss 0:00.27 -csh (csh) 2571 v0 R+ 0:00.00 ps -r
The switches I've mentioned are the most commonly used switches for the ps utility; you can read the manpage for ps to see what other switches are available so you can find out which combo of switches tweaks the output to your liking.
When using ps, you will most likely come across processes that you've never heard of before; use the whatis command to see which manpages will shed light on the mystery. For example, being the very curious type, I tried the following:
whatis init syncer adjkerntz inetd portmap rpc.statd
init(8) - process control initialization
syncer(4) - filesystem synchronizer kernel process
adjkerntz(8) - adjust local time CMOS clock to reflect time zone changes and keep current timezone offset for the kernel
inetd.conf(5), inetd(5) - internet super-server
portmap(8) - RPC program,version to DARPA port mapper
rpc.statd(8) - host status monitoring daemon
which kept me busy reading for a while. It should also give you lots to do til next week, when we'll look at what we can do with all of this newfound knowledge.
Dru Lavigne is a network and systems administrator, IT instructor, author and international speaker. She has over a decade of experience administering and teaching Netware, Microsoft, Cisco, Checkpoint, SCO, Solaris, Linux, and BSD systems. A prolific author, she pens the popular FreeBSD Basics column for O'Reilly and is author of BSD Hacks and The Best of FreeBSD Basics.
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