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Proc - Status file

To get the status information of a process, all you have to do is read the file /proc/PID/status:

cat /proc/self/status

returns:

Name:   cat
State:  R (running)
Tgid:   5452
Pid:    5452
PPid:   743
TracerPid:      0						(2.4)
Uid:    501     501     501     501
Gid:    100     100     100     100
FDSize: 256
Groups: 100 14 16
VmPeak:     5004 kB
VmSize:     5004 kB
VmLck:         0 kB
VmHWM:       476 kB
VmRSS:       476 kB
VmData:      156 kB
VmStk:        88 kB
VmExe:        68 kB
VmLib:      1412 kB
VmPTE:        20 kb
VmSwap:        0 kB
Threads:        1
SigQ:   0/28578
SigPnd: 0000000000000000
ShdPnd: 0000000000000000
SigBlk: 0000000000000000
SigIgn: 0000000000000000
SigCgt: 0000000000000000
CapInh: 00000000fffffeff
CapPrm: 0000000000000000
CapEff: 0000000000000000
CapBnd: ffffffffffffffff
voluntary_ctxt_switches:        0
nonvoluntary_ctxt_switches:     1

This shows you nearly the same information you would get if you viewed it with the ps command. In fact, ps uses the proc file system to obtain its information. But you get a more detailed view of the process by reading the file /proc/PID/status.