Software Layers 2 Introduction to unix 2

Process Monitoring: ps, time, which

Download 0.58 Mb.

Page	6/26
Date	28.01.2017
Size	0.58 Mb.
	#10070

1 2 3 4 5 6 7 8 9 ... 26

Process Control Commands: kill, fg, bg, nice

Process Monitoring: ps, time, which

p
The outputs are:

PID: Process Id (a unique number)

TTY: the text window

S: the state of the process

R - running

S, I - sleeping or idle process

T - stopped process

TIME: process runtime

CMD: the text cmd that started the process

The other outputs (for the -f option) are:

UID: User Id (account name)

PPID: Parent Process Id (also unique)

C: the process CPU usage (%)

STIME: the process start time
s  views current processes
ps -f  views full details of current processes

eg:

% ps

PID TTY S TIME CMD

1001 ttyx6 S 0:00.37 -sh (tcsh)

15411 ttyx6 I 0:00.01 sh -c /bin/sh -c /local/user/.menu

18870 ttyx6 I 0:00.01 /bin/sh -c /local/user/.menu

23641 ttyx6 I 0:00.30 /local/bin/menuaccess

% ps -f

UID PID PPID C STIME TTY TIME CMD

sci-jjh 101 23515 0.0 09:56:53 ttyx6 0:00.38 -sh (tcsh)

sci-jjh 1541 23641 0.0 09:56:50 ttyx6 0:00.01 sh -c /bin/sh -c/local

sci-jjh 1880 15411 0.0 09:56:51 ttyx6 0:00.01 /bin/sh -c/local/user/

sci-jjh 2361 22646 0.0 09:56:33 ttyx6 0:00.30

/local/bin/menuaccess

note: PID & PPID are unique  system can identify & control all processes

note: CPU usages are mostly 0, because when the ps process is running, most other processes stopped

time  determines the time a cmd takes to execute.

There are two forms:

time  a built-in cmd
/usr/bin/time  separate executable program

eg:

>
The output format for time is: U S E P X+D I+O F+W

For our purposes, the main ones are:

U  user time (CPU seconds not including system calls)
S  system time (CPU seconds for system calls only)
E  elapse time (overall time to run the process)
P  user and system time as a percentage of elapse time

For /usr/bin/time the outputs are:

real  the overall time in seconds
user  the user time (U)
sys  the system time (S)

time ps -f

UID PID PPID C STIME TTY TIME CMD

sci-jjh 6502 20278 0.0 15:38:55 ttyt5 0:00.04 /local/bin/menu

access.

sci-jjh 14495 6502 0.0 15:38:57 ttyt5 0:00.37 -sh (tcsh)

sci-jjh 19498 23668 0.0 15:38:55 ttyt5 0:00.01 sh -c /bin/sh -c

/local

sci-jjh 20278 19498 0.0 15:38:55 ttyt5 0:00.01 /bin/sh -c

> /usr/bin/time ps -f

UID PID PPID C STIME TTY TIME CMD

sci-jjh 4116 14495 0.0 16:30:17 ttyt5 0:00.01 /usr/bin/time ps -f

sci-jjh 6502 20278 0.0 15:38:55 ttyt5 0:00.04 /local/bin/menu

access.

sci-jjh 14495 6502 0.0 15:38:57 ttyt5 0:00.38 -sh (tcsh)

sci-jjh 19498 23668 0.0 15:38:55 ttyt5 0:00.01 sh -c /bin/sh -c

/local
real 0.2

user 0.0

sys 0.1

which  displays the absolute pathname of a program. (useful if several versions exist)

eg: on barra ps has two versions: /sbin/ps & /usr/bin/ps

% whereis ps

ps: /sbin/ps /usr/bin/ps

% which ps

/usr/bin/ps

So in this case, /usr/bin/ps is used.

Process Control Commands: kill, fg, bg, nice

For a currently active process:

^C  (control-c) terminates the process
^Z  suspends the process

kill
 terminates process corresponding to PID

eg: Lets say we are looking at a file called summary using the cmd less:

% less summary

if test $# != 1

then echo 'wrong number of arguments'

else cd $1

set - *

……………

We type ^Z to suspend less summary  then use ps to see PID’s  & then we can kill that process

Suspended

% ps

PID TTY S TIME CMD

1001 ttyx6 S 0:00.42 -sh (tcsh)

15411 ttyx6 I 0:00.01 sh -c /bin/sh -c /local/user/.menu

24864 ttyx6 T 0:00.02 less summary

% kill 24864

[1] Terminated less summary

bg  places most recently suspended process into background (still running, but without control of text window) note: To start a process in background, add & to the end of cmd
fg  restores most recent background process to foreground (has control of text window)

nice  runs a cmd slowly (useful if cmd requires lots of CPU time)

note: Using nice will allow other processes more CPU time  this is a CPU-intensive cmd

eg. nice ps aux  makes ps aux run slowly

Directory: student
student -> How to Create a Student Recital Program
student -> Tracks, Mixes, Masters, and More!: Analyzing Preservation Priorities for Multitrack Recordings
student -> A chronology 1660-1832 The Restoration Settlement
student -> Introduction
student -> Disaster planning and recovery: post-katrina lessons for mixed media collections
student -> Comparing Hurricanes and Hurricane Seasons
student -> Storm Surge: a rising Danger
student -> Dr. Jeff Masters' WunderBlog
student -> April 9, 2008 Hurricanes (Continued)
student -> Instructions for Writing Hurricane Term Paper

Download 0.58 Mb.

Share with your friends:

1 2 3 4 5 6 7 8 9 ... 26