network diagnose

#change hostname
echo "HOSTNAME=<ur_hostname>" >> /etc/sysconfig/network

#server lookup
#hostnames: /etc/hosts
#dns: /etc/resolv.conf

#nic configuration: /etc/sysconfig/network-scripts/

#gateway
netstat -rn

#port defination: /etc/services

#restart network
/etc/rc.d/init.d/network restart

#to change the IP address to 192.168.0.10 temporarily
ifconfig eth0 inet 192.168.0.10 netmask 255.255.255.0

#adds a route to the network 192.56.76.x via "eth0".
route add -net 192.56.76.0 netmask 255.255.255.0 eth0

#nmap & netstat deserve another article
--
For many are called, but few are chosen.
-- Matthew 22:14

Re: [dyno's blog for tech] string manipulation in bash script

#!/bin/sh
#basic string manipulation using shell script

set -v

s=" hello world! racn4 "
# 01234567890123456789

#length
echo ${#s}
expr length "$s"

#index
ss='world'
expr index "$s" $ss

#substr
echo ${s:14}
echo ${s:14:4}
echo ${s:(-2)}

#match
[[ $s =~ "o.*o" ]] && echo "yes"
(echo $s | grep -q "o.*o") && echo "yes"

#trim space
s=${s%% }
s=${s## }
echo "<${s}>"

#basic replace
echo ${s/o/O}
echo ${s/#h/O}
echo ${s/%racn4/O}
echo ${s//o/O}

#trim pre/postfix
echo ${s#h*o}
echo ${s##h*o}
echo ${s%o*4}
echo ${s%%o*4}

#upper/lower case
echo $(tr 'a-z' 'A-Z' <<< $s)

#comparation
[[ $s > "hello" ]] && echo "hello"

#number conversion
x="2"; y=3
echo $(($x + $y))

#for more complicated manipulation using grep/sed/awk instead

--
For many are called, but few are chosen.
-- Matthew 22:14