IP address, MAC address and netmask

ifconfig will print out all the network interfaces and their information including the IP address and netmask.

$ ifconfig

A typical output is like this:

eth0      Link encap:Ethernet  HWaddr 00:26:22:A1:25:0F
inet addr:143.89.135.175  Bcast:143.89.135.255  Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
RX packets:305973 errors:0 dropped:0 overruns:0 frame:0
TX packets:337971 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:196287324 (187.1 MiB)  TX bytes:134890044 (128.6 MiB)
Interrupt:30

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:274 errors:0 dropped:0 overruns:0 frame:0
TX packets:274 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:37244 (36.3 KiB)  TX bytes:37244 (36.3 KiB)

eth0 is the network interface. lo is the loopback device.

The IP address is shown in inet addr field.

DNS server, hosts file and DNS look up order

The DNS server for Linux to contact is stored in /etc/resolve.conf. The DNS server(s) can be listed by:

$ cat /etc/resolve.conf

A line like this specifies the DNS server:

nameserver 8.8.8.8

The hosts file for Linux is stored in /etc/hosts. The first two lines (127.0.0.1 and ::1) which map the localhost name shouldn’t be changed since localhost is used for interprocess communication.

127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
10.0.1.8   mysite.mydomain mysite

The order of DNS look up is defined in /etc/nsswitch.conf. Whether the hosts file should be looked up first can be defined. The line in /etc/nsswitch.conf for DNS look up order is:

hosts:          dns [!UNAVAIL=return] files

Gateway

The gateway can be find out by looking at the rules in route table:

$ ip route show

A line like this defines the gateway:

default via 143.89.135.254 dev eth0  proto static

Host name

The host name is specified in /etc/sysconfig/network. The HOSTNAME variable is for the machine’s host name:

HOSTNAME=localhost.localdomain

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First, find out Fixforx’s profile directory in the home directory (I believe most of the users on Linux use Firefox. If you are not using Firefox, what you need to do is try it ;) . It has a format like this:

~/.mozilla/firefox/xxxxxxxx.default

xxxxxxxx is a random string that’s different for different users. You can easily find it out by looking into the directory ~/.mozilla/firefox.

There are two ways to do this: using all-in-one command or putting configurations into profile. The all-in-one-command way needs no other configurations except the command line itself, while the way using configuration has a clearer command.

All-in-one command

This is an all-in-one command that sends email to $TO_EMAIL_ADDRESS

mailx -v -s "$EMAIL_SUBJECT" \
-S smtp-use-starttls \
-S ssl-verify=ignore \
-S smtp-auth=login \
-S smtp=smtp://smtp.gmail.com:587 \
-S from="$FROM_EMAIL_ADDRESS($FRIENDLY_NAME)" \
-S smtp-auth-user=$FROM_EMAIL_ADDRESS \
-S smtp-auth-password=$EMAIL_ACCOUNT_PASSWORD \
-S ssl-verify=ignore \
-S nss-config-dir=~/.mozilla/firefox/xxxxxxxx.default/ \
$TO_EMAIL_ADDRESS

Replace the $XXX with the value that is actually used. The meaning is obvious. And remember to change xxxxxxxx to the string that’s part of the Firefox profile directory.

This command will ask for the email content. Type in the mail content and after finishing the email, use “Ctrl+d” to tell mailx you have finished. Then this mail will be sent out through gmail’s smtp server. You can also use pipe like this:

echo "The mail content" | mail -v -s ...

Using configuration file

There are too many options in the above command? Yes… I must confess so. We can write most of them into mailx/mail’s configuration file ~/.mailrc

set smtp-use-starttls
set nss-config-dir=~/.mozilla/firefox/xxxxxxxx.default/
set ssl-verify=ignore
set smtp=smtp://smtp.gmail.com:587
set smtp-auth=login
set smtp-auth-user=$FROM_EMAIL_ADDRESS
set smtp-auth-password=$EMAIL_ACCOUNT_PASSWORD
set from="$FROM_EMAIL_ADDRESS($FRIENDLY_NAME)"

Change the $XXX and xxxxxxx to the right value for you. When sending mails, use this command:

mailx -v -s "$EMAIL_SUBJECT" $TO_EMAIL_ADDRESS

Then, time to enjoy it!

Updated history
Mar. 11 2010
Apr. 29 2010. Add title.
Jul. 12, 2010. Revise the article.
Jul. 26, 2010. Add highlight colour to pre tags.

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Link here: http://www.tldp.org/LDP/abs/html/index.html

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# .bashrc

# Source global definitions
if [ -f /etc/bashrc ]; then
. /etc/bashrc
fi

# User specific aliases and functions
. ~/.alias

# export GTK_IM_MODULE=ibus

##################################
~/.alias
alias rm=’rm -i’
alias l=’ll -h’

##################################
~/.lftprc

set ftp:charset GBK
set file:charset UTF-8
#set net:connection-limit 30
set net:reconnect-interval-base 12
set net:reconnect-interval-multiplier 1

##################################
.fonts.conf

Fedora-中文字体设置

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复制一份系统的到自己的目录：
cp /etc/DIR_COLORS ~/.dir_colors

修改 .dir_colors

示例
…
# Below are the color init strings for the basic file types. A color init
# string consists of one or more of the following numeric codes:
# Attribute codes:
# 00=none 01=bold 04=underscore 05=blink 07=reverse 08=concealed
# Text color codes:
# 30=black 31=red 32=green 33=yellow 34=blue 35=magenta 36=cyan 37=white
# Background color codes:
# 40=black 41=red 42=green 43=yellow 44=blue 45=magenta 46=cyan 47=white
NORMAL 00 # global default, although everything should be something.
FILE 00 # normal file
DIR 01;34;47 # directory
…

DIR 01;34;47 # directory
表示文件夹字体为粗体白底蓝色。这样看起来好多了。

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