Securing-Optimizing-RH-Linux-1_2_465
Comments and suggestions concerning this book should be mailed to gmourani@videotron.ca
© Copyright 1999-2000 Gerhard Mourani and Open Network Architecture ®
465
Tweaks, Tips and Administration tasks
Some of the tips in this section are specific to Linux systems. Most are applicable to UNIX system
in general.
1.0 The du utility command
You can use the "du" utility to estimate file space usage. For example, to determine in megabyte
the sizes of the "/var/log/" and "/home/" directories trees, type the following command:
[root@deep /]# du -sh /var/log /home
3.5M
/var/log
350M
/home
Keep in mind that the above command will report the actual size of your data. Now that you know
for example that /home is using 350M you can move into it and "du -sh *" to locate where the
largest files are.
[root@deep /]# cd /home/
[root@deep /home]# du -sh *
343M
admin
11k
ftp
6.8M
httpd
12k
lost+found
6.0k
named
6.0k
smbclient
6.0k
test
8.0k
www
NOTE: You can add to your crontab this command so that every day you get emailed the desire
disk space list and youll be able to monitor it without logging in constantly.
1.1 Find out the route that the packets sent from your machine to a remote host
If you want to find out the route that the packets sent from your machine to a remote host, simply
issue the following command:
[root@deep /]# traceroute www.redhat.com
traceroute to www.portal.redhat.com (206.132.41.202), 30 hops max, 38 byte packets
1 ppp005.108-253-207.mtl.mt.videotron.net (207.253.108.5) 98.584 ms 1519.806 ms 109.911 ms
2 fa5-1-0.rb02-piex.videotron.net (207.96.135.1) 149.888 ms 89.830 ms 109.914 ms
3 ia-tlpt-bb01-fec1.videotron.net (207.253.253.53) 149.896 ms 99.873 ms 139.930 ms
4 ia-cduc-bb02-ge2-0.videotron.net (207.253.253.61) 99.897 ms 169.863 ms 329.926 ms
5 if-4-1.core1.Montreal.Teleglobe.net (207.45.204.5) 409.895 ms 1469.882 ms 109.902 ms
6 if-1-1.core1.NewYork.Teleglobe.net (207.45.223.109) 189.920 ms 139.852 ms 109.939 ms
7 206.132.150.133 (206.132.150.133) 99.902 ms 99.724 ms 119.914 ms
8 pos1-0-2488M.wr2.CLE1.gblx.net (206.132.111.89) 189.899 ms 129.873 ms 129.934 ms
9 pos8-0-2488m.wr2.kcy1.globalcenter.net (206.132.111.82) 169.890 ms 179.884 ms 169.933 ms
10 206.132.114.77 (206.132.114.77) 199.890 ms 179.771 ms 169.928 ms
11 pos8-0-2488M.wr2.SFO1.gblx.net (206.132.110.110) 159.909 ms 199.959 ms 179.837 ms
12 pos1-0-2488M.cr1.SNV2.gblx.net (208.48.118.118) 179.885 ms 309.855 ms 299.937 ms
13 pos0-0-0-155M.hr2.SNV2.gblx.net (206.132.151.46) 329.905 ms 179.843 ms 169.936 ms
14 206.132.41.202 (206.132.41.202) 2229.906 ms 199.752 ms 309.927 ms
Where <www.redhat.com> is the name or ip address of the host that you want to trace.