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:

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.

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.

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:

You can display detailed, technical information about processes or control active processes by using some of the process commands. Table 19–3 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 19, 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:

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

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.

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.

# 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

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