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 <[email protected]> wrote: From: b.sadhiq <[email protected]> Subject: [Linux_Mantra] Daily Tips To: [email protected] 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/ [Non-text portions of this message have been removed]
