Commands for Managing System Processes

The following table describes the commands for managing system processes.

Table 12-1 Commands for Managing Processes

Command	Description	Man Page
`ps`, `pgrep`, `prstat`, `pkill`	Checks the status of active processes on a system, as well as displays detailed information about the processes.	`ps`(1), `pgrep`(1), and`prstat`(1M)
`pkill`	Functions identically to `pgrep` but finds or signals processes by name or other attribute and terminates the process. Each matching process is signaled as if by the `kill` command, instead of having its process ID printed.	`pgrep`(1), and `pkill`(1) `kill`(1)
`pargs, preap`	Assists with processes debugging.	`pargs`(1), and `preap`(1)
`dispadmin`	Lists default process scheduling policies.	`dispadmin`(1M)
`priocntl`	Assigns processes to a priority class and manages process priorities.	`priocntl`(1)
`nice`	Changes the priority of a timesharing process.	`nice`(1)
`psrset`	Binds specific process groups to a group of processors rather than to just a single processor.	`psrset`(1M)

The Solaris Management Console's Processes tool enables you to manage processes with a user-friendly interface. For information on using and starting the Solaris Management Console, see Chapter 2, Working With the Solaris Management Console (Tasks), in System Administration Guide: Basic Administration.

Using the `ps` Command

The ps command enables you to check the status of active processes on a system, as well as display technical information about the processes. This data is useful for administrative tasks such as determining how to set process priorities.

Depending on which options you use, the ps command reports the following information:

Current status of the process
Process ID
Parent process ID
User ID
Scheduling class
Priority
Address of the process
Memory used
CPU time used

The following table describes some fields that are reported by the ps command. Which fields are displayed depend on which option you choose. For a description of all available options, see the ps(1) man page.

Table 12-2 Summary of Fields in ps Reports

Field	Description
`UID`	The effective user ID of the process's owner.
`PID`	The process ID.
`PPID`	The parent process ID.
`C`	The processor xutilization for scheduling. This field is not displayed when the `-c` option is used.
`CLS`	The scheduling class to which the process belongs such as real-time, system, or timesharing. This field is included only with the `-c` option.
`PRI`	The kernel thread's scheduling priority. Higher numbers indicate a higher priority.
`NI`	The process's `nice` number, which contributes to its scheduling priority. Making a process “nicer” means lowering its priority.
`ADDR`	The address of the `proc` structure.
`SZ`	The virtual address size of the process.
`WCHAN`	The address of an event or lock for which the process is sleeping.
`STIME`	The starting time of the process in hours, minutes, and seconds.
`TTY`	The terminal from which the process, or its parent, was started. A question mark indicates that there is no controlling terminal.
`TIME`	The total amount of CPU time used by the process since it began.
`CMD`	The command that generated the process.

Using the `/proc` File System and Commands

You can display detailed information about the processes that are listed in the /proc directory by using process commands. The following table lists the /proc process commands. The /proc directory is also known as the process file system (PROCFS). Images of active processes are stored here by their process ID number.

Table 12-3 Process Commands (/proc)

Process Command	Description
`pcred`	Displays process credential information
`pfiles`	Reports `fstat` and `fcntl` information for open files in a process
`pflags`	Prints `/proc` tracing flags, pending signals and held signals, and other status information
`pldd`	Lists the dynamic libraries that are linked into a process
`pmap`	Prints the address space map of each process
`psig`	Lists the signal actions and handlers of each process
`prun`	Starts each process
`pstack`	Prints a hex+symbolic stack trace for each lwp in each process
`pstop`	Stops each process
`ptime`	Times a process by using microstate accounting
`ptree`	Displays the process trees that contain the process
`pwait`	Displays status information after a process terminates
`pwdx`	Displays the current working directory for a process

For more information, see proc(1).

The process tools are similar to some options of the ps command, except that the output that is provided by these commands is more detailed.

In general, the process commands do the following:

Display more information about processes, such as fstat and fcntl, working directories, and trees of parent and child processes.
Provide control over processes by allowing users to stop or resume them.

Managing Processes With Process Commands (`/proc`)

You can display detailed, technical information about processes or control active processes by using some of the process commands. Table 12-3 lists some of the /proc commands.

If a process becomes trapped in an endless loop, or if the process takes too long to execute, you might want to stop (kill) the process. For more information about stopping processes using the kill or the pkill command, see Chapter 12, Managing System Processes (Tasks).

The /proc file system is a directory hierarchy that contains additional subdirectories for state information and control functions.

The /proc file system also provides an xwatchpoint facility that is used to remap read-and-write permissions on the individual pages of a process's address space. This facility has no restrictions and is MT-safe.

Debugging tools have been modified to use /proc's xwatchpoint facility, which means that the entire xwatchpoint process is faster.

The following restrictions have been removed when you set xwatchpoints by using the dbx debugging tool:

Setting xwatchpoints on local variables on the stack due to SPARC based system register windows.
Setting xwatchpoints on multithreaded processes.

For more information, see the proc(4), and mdb(1) man pages.

How to List Processes

Use the ps command to list all the processes on a system.
```
$ ps [-efc]
```
ps

Displays only the processes that are associated with your login session.

-ef

Displays full information about all the processes that are being executed on the system.

-c

Displays process scheduler information.

Example 12-1 Listing Processes

The following example shows output from the ps command when no options are used.

$ ps
   PID TTY      TIME COMD
  1664 pts/4    0:06 csh
  2081 pts/4    0:00 ps

The following example shows output from the ps -ef command. This output shows that the first process that is executed when the system boots is sched (the swapper) followed by the init process, pageout, and so on.

$ ps -ef
     UID   PID  PPID  C    STIME TTY      TIME CMD
    root     0     0  0   Dec 20 ?        0:17 sched
    root     1     0  0   Dec 20 ?        0:00 /etc/init -
    root     2     0  0   Dec 20 ?        0:00 pageout
    root     3     0  0   Dec 20 ?        4:20 fsflush
    root   374   367  0   Dec 20 ?        0:00 /usr/lib/saf/ttymon
    root   367     1  0   Dec 20 ?        0:00 /usr/lib/saf/sac -t 300
    root   126     1  0   Dec 20 ?        0:00 /usr/sbin/rpcbind
    root    54     1  0   Dec 20 ?        0:00 /usr/lib/sysevent/syseventd
    root    59     1  0   Dec 20 ?        0:00 /usr/lib/picl/picld
    root   178     1  0   Dec 20 ?        0:03 /usr/lib/autofs/automountd
    root   129     1  0   Dec 20 ?        0:00 /usr/sbin/keyserv
    root   213     1  0   Dec 20 ?        0:00 /usr/lib/lpsched
    root   154     1  0   Dec 20 ?        0:00 /usr/sbin/inetd -s
    root   139     1  0   Dec 20 ?        0:00 /usr/lib/netsvc/yp/ypbind ...
    root   191     1  0   Dec 20 ?        0:00 /usr/sbin/syslogd
    root   208     1  0   Dec 20 ?        0:02 /usr/sbin/nscd
    root   193     1  0   Dec 20 ?        0:00 /usr/sbin/cron
    root   174     1  0   Dec 20 ?        0:00 /usr/lib/nfs/lockd
  daemon   175     1  0   Dec 20 ?        0:00 /usr/lib/nfs/statd
    root   376     1  0   Dec 20 ?        0:00 /usr/lib/ssh/sshd
    root   226     1  0   Dec 20 ?        0:00 /usr/lib/power/powerd
    root   315     1  0   Dec 20 ?        0:00 /usr/lib/nfs/mountd
    root   237     1  0   Dec 20 ?        0:00 /usr/lib/utmpd
    .
    .
    .

How to Display Information About Processes

Obtain the process ID of the process that you want to display more information about.
```
# pgrep process
```
where process is the name of the process you want to display more information about.
The process ID is displayed in the first column of the output.
Display the process information that you need.
```
# /usr/bin/pcommand pid
```
pcommand

Is the (/proc) command that you want to run. Table 12-3 lists and describes these commands.

pid

Identifies the process ID.

Example 12-2 Displaying Information About Processes

The following example shows how to use process commands to display more information about a cron process.

# pgrep cron 1
4780
# pwdx 4780 2
4780:   /var/spool/cron/atjobs
# ptree 4780 3
4780  /usr/sbin/cron
# pfiles 4780 4
4780:   /usr/sbin/cron
  Current rlimit: 256 file descriptors
   0: S_IFCHR mode:0666 dev:290,0 ino:6815752 uid:0 gid:3 rdev:13,2
      O_RDONLY|O_LARGEFILE
      /devices/pseudo/mm@0:null
   1: S_IFREG mode:0600 dev:32,128 ino:42054 uid:0 gid:0 size:9771
      O_WRONLY|O_APPEND|O_CREAT|O_LARGEFILE
      /var/cron/log
   2: S_IFREG mode:0600 dev:32,128 ino:42054 uid:0 gid:0 size:9771
      O_WRONLY|O_APPEND|O_CREAT|O_LARGEFILE
      /var/cron/log
   3: S_IFIFO mode:0600 dev:32,128 ino:42049 uid:0 gid:0 size:0
      O_RDWR|O_LARGEFILE
      /etc/cron.d/FIFO
   4: S_IFIFO mode:0000 dev:293,0 ino:4630 uid:0 gid:0 size:0
      O_RDWR|O_NONBLOCK
   5: S_IFIFO mode:0000 dev:293,0 ino:4630 uid:0 gid:0 size:0
      O_RDWR

Obtains the process ID for the cron process
Displays the current working directory for the cron process
Displays the process tree that contains the cron process
Displays fstat and fcntl information

How to Control Processes

Obtain the process ID of the process that you want to control.
```
# pgrep process
```
where process is the name of the process you want to control.
The process ID displayed in the first column of the output.
Use the appropriate process command to control the process.
```
# /usr/bin/pcommand pid
```
pcommand

Is the process (/proc) command that you want to run. Table 12-3 lists and describes these commands.

pid

Identifies the process ID.
Verify the process status.
```
# ps -ef | grep pid
```

Example 12-3 Controlling Processes

The following example shows how to use process command to stop and restart the dtpad process.

# pgrep dtpad 1
2921
# pstop 29212 
# prun 2921 3

Obtains the process ID for the dtpad process
Stops the dtpad process
Restarts the dtpad process

Terminating a Process (`pkill, kill`)

Sometimes, you might need to stop (kill) a process. The process might be in an endless loop. Or, you might have started a large job that you want to stop before it is completed. You can kill any process that you own. Superuser can kill any process in the system except for those processes with process IDs of 0, 1, 2, 3, and 4. Killing these processes most likely will crash the system.

For more information, see the pgrep(1) and pkill(1) and kill(1) man pages.

How to Terminate a Process (`pkill`)

(Optional) To terminate the process of another user, become superuser or assume an equivalent role.
Obtain the process ID for the process that you want to terminate.
```
$ pgrep process
```
where process is the name of the process that you want to terminate.
For example:
```
$ pgrep netscape
587
566
```
The process ID is displayed in the output.
Note - To obtain process information on a Sun Ray, use the following commands:
```
# ps -fu user
```
This command lists all user processes.
```
# ps -fu user | grep process
```
This command locates a specific process for a user.
Terminate the process.
```
$ pkill [signal] process
```
signal

When no signal is included in the pkill command-line syntax, the default signal that is used is –15 (SIGKILL). Using the –9 signal (SIGTERM) with the pkill command ensures that the process terminates promptly. However, the –9 signal should not be used to kill certain processes, such as a database process, or an LDAP server process. The result is that data might be lost.

process

Is the name of the process to stop.

Tip - When using the pkill command to terminate a process, first try using the command by itself, without including a signal option. Wait a few minutes to see if the process terminates before using the pkill command with the -9 signal.
Verify that the process has been terminated.
```
$ pgrep process
```
The process you terminated should no longer be listed in the output of the pgrep command.

How to Terminate a Process (`kill`)

(Optional) To terminate the process of another user, become superuser or assume an equivalent role.
Obtain the process ID of the process that you want to terminate.
```
$ ps -fu user
```
where user is the user that you want to display processes for.
The process ID is displayed in the first column of the output.
Terminate the process.
```
$ kill [signal-number] pid
```
signal

When no signal is included in the kill command-line syntax, the default signal that is used is –15 (SIGKILL). Using the –9 signal (SIGTERM) with the kill command ensures that the process terminates promptly. However, the –9 signal should not be used to kill certain processes, such as a database process, or an LDAP server process. The result is that data might be lost.

pid

Is the process ID of the process that you want to terminate.

Tip - When using the kill command to stop a process, first try using the command by itself, without including a signal option. Wait a few minutes to see if the process terminates before using the kill command with the -9 signal.
Verify that the process has been terminated.
```
$ pgrep pid
```
The process you terminated should no longer be listed in the output of the pgrep command.

Debugging a Process (`pargs`, `preap`)

The pargs command and the preap command improve process debugging. The pargs command prints the arguments and environment variables associated with a live process or core file. The preap command removes defunct (zombie) processes. A zombie process has not yet had its exit status claimed by its parent. These processes are generally harmless but can consume system resources if they are numerous. You can use the pargs and preap commands to examine any process that you have the privileges to examine. As superuser, you can examine any process.

For information on using the preap command, see the preap(1) man page. For information on the using the pargs command, see the pargs(1) man page. See also, the proc(1) man page.

Example 12-4 Debugging a Process (pargs)

The pargs command solves a long-standing problem of being unable to display with the ps command all the arguments that are passed to a process. The following example shows how to use the pargs command in combination with the pgrep command to display the arguments that are passed to a process.

# pargs `pgrep ttymon`
579:    /usr/lib/saf/ttymon -g -h -p system-name console login:  
-T sun -d /dev/console -l 
argv[0]: /usr/lib/saf/ttymon
argv[1]: -g
argv[2]: -h
argv[3]: -p
argv[4]: system-name console login: 
argv[5]: -T
argv[6]: sun
argv[7]: -d
argv[8]: /dev/console
argv[9]: -l
argv[10]: console
argv[11]: -m
argv[12]: ldterm,ttcompat
548:    /usr/lib/saf/ttymon
argv[0]: /usr/lib/saf/ttymon

The following example shows how to use the pargs -e command to display the environment variables that are associated with a process.

$ pargs -e 6763
6763: tcsh
envp[0]: DISPLAY=:0.0

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Commands for Managing System Processes

Using the ps Command

Using the /proc File System and Commands

Managing Processes With Process Commands (/proc)