Unix for Advanced Users - Process Management under Unix - Process States

10. Process Management under Unix

10.4. Process States - Resident, Sleeping, Zombie Processes

As we saw before, the Unix command used to check on the status of currently running processes is ps. There are two flavors of ps - the SVR4 ps and the BSD ps. Tru64UNIX (formerly Digital UNIX), HP-UX, Irix, and Solaris use the SVR4-ish flavor while AIX and Linux use the BSD-ish flavor. The main differnce is that one uses ps -ef to take at all running process under SVR4 and ps aux under BSD.

The following shows a typical SVR4 ps -al output (on Solaris):

dhruv% ps -al
 F S   UID   PID  PPID  C PRI NI     ADDR     SZ    WCHAN TTY      TIME CMD
 8 S 27017   320   295  0  59 20 60366020    113 60366090 console  0:00 openwin
 8 S 27017   325   320  0  54 20 608a8660    230 608a86d0 console  0:00 xinit
 8 S 27017   326   325  0  41 20 60ad5988   2819 6007fa16 console 6253:07 Xsun
 8 S 27017   327   325  0  54 20 60ad4008    112 60ad4078 console  0:00 sh
 8 S 27017   333   329  0  51 20 60add990    279 6007ff8e pts/0    2:56 fvwm2
 8 S 27017   337   333  0  41 20 60add330    248 6007e846 pts/0    0:04 FvwmButt
 8 S 27017   341   333  0  41 20 60adccd0    247 6007e31e pts/0    0:15 FvwmPage
 8 S 27017 21330     1  0  41 20 60ae7998   3064 606967a6 pts/0    5:28 netscape
 8 S     0 21626 15596  0  41 20 60af9340    215 606968e6 pts/8    0:01 ssh1
 8 O     0 21938 21901  0  41 20 60ae6018    104          pts/1    0:00 ps
 8 S 27017 21331 21330  0  51 20 609d9340   1404 6007e346 pts/0    0:00 netscape
 8 S 27017 21239 19355  0  41 20 60b10660    215 6069677e pts/9    0:09 mutt
 8 S     0 21382 19382  0  41 20 609d8680    216 6007e18e pts/10   0:01 ssh1
 8 R 27017 21901 21900  0  51 20 60adc670    153          pts/1    0:00 tcsh

The second column shows which state the process is in. You should check the man page for your version of ps to make sure, but the usual convention is:

(The O on line 10 in SVR4 ps under Solaris means the process is currently running on a CPU.)

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