Proc - Process Status file

The /proc/<PID>/stat file contains detailed information about the process itself. Its fields are explained here:

Contents of the stat files (as of 2.6.30-rc7)

Field	Content
pid	Process id.
tcomm	Filename of the executable.
state	State (R is running, S is sleeping, D is sleeping in an uninterruptible wait, Z is zombie, T is traced or stopped).
ppid	Process id of the parent process.
pgrp	pgrp of the process.
sid	Session id.
tty_nr	tty the process uses.
tty_pgrp	pgrp of the tty.
flags	Task flags.
min_flt	Number of minor faults.
cmin_flt	Number of minor faults with child's.
maj_flt	Number of major faults.
cmaj_flt	Number of major faults with child's.
utime	User mode jiffies.
stime	Kernel mode jiffies.
cutime	User mode jiffies with child's.
cstime	Kernel mode jiffies with child's.
priority	Priority level.
nice	Nice level.
num_threads	Number of threads.
it_real_value	Obsolete, always 0.
start_time	Time the process started after system boot.
vsize	Virtual memory size.
rss	Resident set memory size.
rsslim	Current limit in bytes on the rss.
start_code	Address above which program text can run.
end_code	Address below which program text can run.
start_stack	Address of the start of the stack.
esp	Current value of ESP.
eip	Current value of EIP.
pending	Bitmap of pending signals.
blocked	Bitmap of blocked signals.
sigign	Bitmap of ignored signals.
sigcatch	Bitmap of catched signals.
wchan	Address where process went to sleep.
0	Place holder.
0	Place holder.
exit_signal	Signal to send to parent thread on exit.
task_cpu	Which CPU the task is scheduled on.
rt_priority	Realtime priority.
policy	Scheduling policy (man sched_setscheduler).
blkio_ticks	Time spent waiting for block IO.
gtime	Guest time of the task in jiffies.
cgtime	Guest time of the task children in jiffies.