some unix system admin questions

Can anyone answer following questions? Thanks!

8. Please ignore that artificial line feeds introduced by Word in the following question:
We have a web log from apache httpd server which can be like:

128.249.149.23 - - [19/Mar/2002:17:14:06 -0500] "GET
/entrez/query.fcgi?cmd=Retrieve&db=OMIM&dopt=Detailed&tmpl=dispomimTemplate&list
_uids=602321 HTTP/1.0" 200 12299 1
"http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?SUBMIT=y"
62.219.219.182 - - [19/Mar/2002:17:14:06 -0500] "GET /corehtml/ncbi_test.css
HTTP/1.1" 304 - 0 "http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?CMD=&DB=PubMed"
62.219.219.182 - - [19/Mar/2002:17:14:21 -0500] "GET
/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10236068&dopt=Abstract
HTTP/1.1" 200 16082 0
"http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?CMD=&DB=PubMed"
132.239.159.125 - - [19/Mar/2002:17:14:22 -0500] "GET /corehtml/transparent.gif
HTTP/1.0" 304 - 0
"http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?CMD=search&DB=PubMed"
132.239.159.125 - - [19/Mar/2002:17:14:22 -0500] "GET /corehtml/GoUp2.gif
HTTP/1.0" 304 - 0
"http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?CMD=search&DB=PubMed"
132.239.159.125 - - [19/Mar/2002:17:14:22 -0500] "GET /entrez/query/gifs/2.gif
HTTP/1.0" 200 93 0
"http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?CMD=search&DB=PubMed"
18.79.0.32 - - [19/Mar/2002:17:14:22 -0500] "GET
/entrez/utils/fref.fcgi?http://www.pnas.org/cgi/pmidlookup?...ull&pmid=937176
8 HTTP/1.0" 302 318 0
"http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_ui
ds=9371768&dopt=Abstract"
155.41.134.187 - - [19/Mar/2002:17:14:23 -0500] "POST
/entrez/query.fcgi?SUBMIT=y HTTP/1.1" 200 35998 1
"http://www4.ncbi.nlm.nih.gov/PubMed/"
130.207.65.145 - - [19/Mar/2002:17:14:24 -0500] "GET /blast/html/corner_bl.gif
HTTP/1.0" 200 196 0
"http://www.ncbi.nlm.nih.gov/blast/Blast.cgi?CMD=Web&LAYOUT=TwoWindows&AUTO_FORM
AT=Semiauto&PAGE=Nucleotides&NCBI_GI=yes&FILTER=L&HITLIST_SIZE=100&SHOW_OVERVIEW
=yes&AUTO_FORMAT=yes"
129.100.249.27 - - [19/Mar/2002:17:14:24 -0500] "GET /corehtml/bkgd.gif
HTTP/1.0" 304 - 0
"http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=
11803231&dopt=Abstract"

The log is huge and updated continuously by the server.
The problem is to find:
a) how to roughly estimate the number of requests processed per second.
b) top ten hosts who send most of the requests to us for last 30 minutes.
The unix text processing tools like sort, awk, uniq, cut, sed should be used.



9. How can I check, on a Unix system, the number of network interfaces?



10. How to find out the IP address and netmask associated with network
interface?


11. A user complains that his or her machine has become quite slow, compared to its previous performance. What commands may be used to find why the machine slowed?

12. How can I check what dynamic libraries are needed to run the particular binary file on linux/solaris?



13. What's the difference between a system call and library function?

a) apache comes with a benchmarking utility called ab (man ab will show its man pages) It will tell you what you need to know

b) There are lots of systems for this sort of stuff. the most common one is Webalizer is probably the most popular and can be found here :http://www.mrunix.net/webalizer/



you haven't indicated what flavour of UNIX you are using, but from my Linux knowledge, may I recommend the ifconfig -a command. It will present results as below:

eth0 Link encap:Ethernet HWaddr 00:E0:18:19:02:7A
inet addr:10.0.0.5 Bcast:10.255.255.255 Mask:255.0.0.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:274569 errors:10 dropped:0 overruns:0 frame:0
TX packets:264299 errors:3 dropped:0 overruns:0 carrier:6
collisions:114 txqueuelen:100
RX bytes:213639351 (203.7 Mb) TX bytes:28102056 (26.8 Mb)
Interrupt:9 Base address:0xac00

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:2229 errors:0 dropped:0 overruns:0 frame:0
TX packets:2229 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:1104682 (1.0 Mb) TX bytes:1104682 (1.0 Mb)




see above




a useful tool for system load diagnostics is top (man top will show the docs). It indiacates uptime, load average, memory usage and a list of running processes in cpu usage order. You can quickly identify greedy processes and if necessary kill them off, or adjust their 'nice' values etc



unless someone can tell me otherwise, this is the sort of thing that can only be resolved by reading the documentation for the application in question. Usually application docs list any required libraries or installarions, often referring to them as 'dependencies'



A system call is when a piece of code spawns a new process by making a call to the shell. The process might just be a shell sequence, or it might start another application. For example, in the following snippet of PERL code, although it doesn't do anything that you might find usful, there is a system calls on line 7. It uses backtick operators to send a sequesnce of commands to the shell (in this case it cd's to the path specified in $ROOT then collects a list of the contents of that directory.

#!/usr/bin/perl
# chris lacy-hulbert
# October 2002

$ROOT="/home/root2/sites/";
chomp($ROOT);
@sites=`cd $ROOT && ls`;

$exclude="/home/root2/exclusions";
open (EXCL, ">>$exclude")|| die "can't list exclusions";
foreach $site (@sites){
chomp $site;
$statspath=$site . "/logs\n";
print EXCL $statspath;
}


A library function is a bit different, because it is usally written in the same language as the calling routine and it doesn't necessarily envoke any child processes.. it is simply a convenient way of modularising code - ie bundle useful functions into a library file and then include that library at the top of any programmes which call the requried functions.

I hope that's sort of accurate/useful

christo

Thank you so much for your reply!
Bin