For Linux_Mantra Members,

 Our  group   is running  with 230 members, but activity made  by them is  
very  less.
As I think "knowledge Is  Every Thing"  and  all members  should  take some  
effort to share their knowledge.

Regards.
b.sadhiq

--- On Sun, 15/2/09, neetesh budholiya <[email protected]> wrote:
From: neetesh budholiya <[email protected]>
Subject: Re: [Linux_Mantra] Daily Tips
To: [email protected]
Date: Sunday, 15 February, 2009, 4:45 PM











    
            Hi Sadhiq

 

you are really doing great work for the admins by sending this daily tips 
mail.I 

appreciates your efforts for this.Thanks



Neetesh Budholiya

9930873363



--- On Sun, 15/2/09, b.sadhiq <b.sad...@yahoo. co.in> wrote:



From: b.sadhiq <b.sad...@yahoo. co.in>

Subject: [Linux_Mantra] Daily Tips

To: Linux_Mantra@ yahoogroups. com

Date: Sunday, 15 February, 2009, 11:16 AM



Who and What is doing What on Your System - finding open sockets,

files etc.



$ lsof

or as root

$ watch lsof -i



To list all open Internet files, use:



$ lsof -i -U



You can also get very specific about ports. Do this as root for low

ports.



$ lsof -i TCP:3306



Or, look at UDP ports as follows:



$ lsof -i UDP:1812



(See TIP 118)



Also try fuser. Suppose you have a mounted file-system, and you need

to umount it. To list the users on the file-system /work



$ fuser -u /work



To kill all processes accessing the file system /work in any way.



$ fuser -km /work



Or better yet, maybe you want to eject a cdrom on /mnt/cdrom



$ fuser -km /mnt/cdrom



If you need IO load information about your system, you can execute

iostat. But note, the very first iostat gives a snapshot since

the last boot. You typically want the following command, which gives

you 3 outputs every 5 seconds.



$ iostat -xtc 5 3

Linux 2.6.12-1.1376_ FC3smp (squeezel.squeezel. com) 10/05/2005



Time: 07:05:04 PM

avg-cpu: %user %nice %system %iowait %idle

0.97 0.06 1.94 0.62 96.41



Time: 07:05:09 PM

avg-cpu: %user %nice %system %iowait %idle

0.60 0.00 1.70 0.00 97.70



Time: 07:05:14 PM

avg-cpu: %user %nice %system %iowait %idle

1.00 0.00 1.60 0.00 97.39



vmstat reports memory statistics. See tip 241 for vmstat for

I/O subsystem total statistics.



$ vmstat

$ ifconfig

$ cat /proc/sys/vm/ .. (entries under here)



*NOTE: (TIP 77) shows sample usage of "ifconfig". Also

(TIP 84) shows sample output of "$ cat /proc/cpuinfo" . You can

download iostat

and other packages from

(http://perso. wanadoo.fr/ sebastien. godard/download_ en.html).

You also may want to look at iozone (TIP 178).



Also



$ cat /proc/meminfo

$ cat /proc/stat



$ cat /proc/uptime

1078623.55 1048008.34 First number is the number of

seconds since boot.

The second number is the number of

idle seconds.



$ cat /proc/loadavg

0.25 0.14 0.10 1/166 7778 This shows load at 1,5, and 15 minutes,

a total of 1 current running

process out

from a total of 166. The 7778 is

the last

process id used.

Ref:

http://www.teamques t.com/resources/ gunther/ldavg1. shtml



Or current process open file descriptors



$ ls -l /proc/self/fd/ 0

lrwx------ 1 chirico chirico 64 Jun 29 13:17 0

-> /dev/pts/51

lrwx------ 1 chirico chirico 64 Jun 29 13:17 1

-> /dev/pts/51

lrwx------ 1 chirico chirico 64 Jun 29 13:17 2

-> /dev/pts/51

lr-x------ 1 chirico chirico 64 Jun 29 13:17 3

-> /proc/26667/ fd



So you could, $ echo "stuff" > /dev/pts/51, to get output. Note,

tree is also

helpful here:



$ tree /proc/self



/proc/self

|-- auxv

|-- cmdline

|-- cwd -> /work/souptonuts/ documentation/ theBook

|-- environ

|-- exe -> /usr/bin/tree

|-- fd

| |-- 0 -> /dev/pts/51

| |-- 1 -> /dev/pts/51

| |-- 2 -> /dev/pts/51

| `-- 3 -> /proc/26668/ fd

|-- maps

|-- mem

|-- mounts

|-- root -> /

|-- stat

|-- statm

|-- status

|-- task

| `-- 26668

| |-- auxv

| |-- cmdline

| |-- cwd -> /work/souptonuts/ documentation/ theBook

| |-- environ

| |-- exe -> /usr/bin/tree

| |-- fd

| | |-- 0 -> /dev/pts/51

| | |-- 1 -> /dev/pts/51

| | |-- 2 -> /dev/pts/51

| | `-- 3 -> /proc/26668/ task/26668/ fd

| |-- maps

| |-- mem

| |-- mounts

| |-- root -> /

| |-- stat

| |-- statm

| |-- status

| `-- wchan

`-- wchan



10 directories, 28 files



Need a listing of the system settings?



$ sysctl -a



Need IPC (Shared Memory Segments, Semaphore Arrays, Message

Queue) status

etc?



$ ipcs

$ ipcs -l "This gives limits"



Need to "watch" everything a user does? The following watches

donkey.



$ watch lsof -u donkey



Or, to see what in going on in directory "/work/junk"



$ watch lsof +D /work/junk



Add more friends to your messenger and enjoy! Go to http://messenger. 
yahoo.com/ invite/



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