Information Technology Reference
In-Depth Information
In some Solaris documentation, pseudo- or memory-based file systems are referred
to as
virtual file systems
. However, this term is also used for file systems created and
managed by virtual disk management systems (covered in Chapter 14). To avoid con-
fusion, memory-based file systems will be referred to strictly as pseudo-file systems.
Process File System (PROCFS)
The
Process File System
is a memory-based file system used to provide process
status and information. There is one instance of
PROCFS
on a system by
default and it is accessible as the
/proc
directory. This directory contains one
directory for each active process on the system. The directory name is the
process ID (PID) of the process. Files under each PID directory provide sta-
tus and other information about the process. The
/proc
directory is owned
by the
root
account and has an access mode of 555 (read/execute for
owner/group/other), because no user account (not even
root
) should attempt
to modify the files. These files are managed directly by the kernel.
The proc Tools
Process status and other information is extracted from the
/proc PROCFS
instance using the
proc tools,
which are a collection of command-line utilities.
Stop/start capability is also provided.
The PID of the process to be examined is specified as a command-line argu-
ment. If more than one process is to be examined, the PIDs should be sepa-
rated by spaces. Table 6.6 provides a list of the proc tools.
Table 6.6
The proc Tools
Command
Purpose
pcred
Lists process credentials (effective and real UID and GID).
pflags
Displays tracing flags, pending and held signals, and other information.
pfiles
Lists information on all open files.
pldd
Lists dynamic link libraries used.
pmap
Displays memory address space map.
prun
Restarts the process.
psig
Lists signal actions.
pstack
Displays a stack trace.
pstop
Stops the process.
ptime
Displays time of process execution.
ptree
Displays process tree (process and any child processes).
pwait
Waits for process to terminate.
pwdx
Displays current working directory.
