/proc filesystem

There is a lot of useful information about all the active processes in "/proc" filesystem, unfortunately you need canot just "cat" the files as "/proc" is not a normal filesystem and contains a snapshot of the current system status, and may well have changed before you get the chance to examine it.  e.g.

# ps
      PID    TTY  TIME CMD
  8847424  pts/0  0:00 -ksh
  9437218  pts/0  0:00 ps

# find /proc/8847424
/proc/8847424
/proc/8847424/as
/proc/8847424/cred
/proc/8847424/ctl
/proc/8847424/cwd
/proc/8847424/fd
/proc/8847424/fd/0
/proc/8847424/fd/1
/proc/8847424/fd/2
/proc/8847424/fd/10
/proc/8847424/fd/63
/proc/8847424/lwp
/proc/8847424/lwp/38404245
/proc/8847424/lwp/38404245/lwpctl
/proc/8847424/lwp/38404245/lwpsinfo
/proc/8847424/lwp/38404245/lwpstatus
/proc/8847424/map
/proc/8847424/object
/proc/8847424/object/a.out
/proc/8847424/object/jfs2.10.5.487607
/proc/8847424/object/jfs2.10.5.1664
/proc/8847424/object/jfs2.10.5.4220
/proc/8847424/object/jfs2.10.5.13168
/proc/8847424/object/jfs2.10.5.339
/proc/8847424/object/jfs2.10.5.4250
/proc/8847424/psinfo
/proc/8847424/sigact
/proc/8847424/status
/proc/8847424/sysent
/proc/8847424/root
/proc/8847424/mmap

Just listing the "/proc" filesystem tree for a process does give you a good idea of what the system is doing and which resources it requires, however you need to use specialist tools such as:

Tool	Description
procstack	Get Process Stack Trace
procflags	Show Pending and Held Signals for Process
procsig	Display Signal Action and Handlers for Process
procfiles -n pid	Report stat and fcntl Info for All Open Files in Each Process
procwdx	Display the Current Working Directory of the Process
proctree	Display the Process Tree

to get more information.

The "/proc" entries contain the following information:

Directory or filename	Description
/proc/pid/as	Address space used by this process.
/proc pid/cred	Contains a description of the credentials associated with this process.
/proc/pid/ctl	Process control file.
/proc/pid/cwd	A link that provides access to the current working directory of this process. Any process can access the current working directory of the process through this ink, provided it has the necessary permissions. If you run "strings" against this file it gives the same output as "ls".
/proc/pid/fd	Contains files for all open file descriptors for this process.
/proc/pid/map	Address space map for this process.
/proc/pid/object	Directory for objects.
/proc/pid/psinfo	Process status information.
/proc/pid/sigact	Signal actions for this process.
/proc/pid/status	Process status.
/proc/pid/sysent	System call information for process PID.
Thread specific files
/proc/pid/lwp/tid	Directory for thread.
/proc/pid/lwp/tid/lwpctl	Control file for thread.
/proc/pid/lwp/tid/lwpsinfo	Process status info for thread.
/proc/pid/lwp/tid/lwpstatus	Status of thread.