Where Does Linux Save Wireless Card Settings?

Q. I'd like to get more information about my wireless settings stored under CentOS / RHEL / Fedora Linux. Where Does Linux Save Wireless Card Settings?

A. Linux saves network related settings under /etc directory. Different Linux distribution uses different file names.

Red Hat / RHEL / CentOS / Fedora Linux Settings File

Edit file /etc/sysconfig/network-scripts/ifcfg-ethX or /etc/sysconfig/network-scripts/ifcfg-wmasterX. Usually ifcfg-wmasterX file is for wireless and ifcfg-ethX is for each wired interface. It is recommended that you use GUI tool called system-config-network to modify / edit / setup wireless settings. Open terminal and type the command:
system-config-network
The Network Administration Tool (system-config-network) is an easy way to make changes to the various network interface configuration files.

Debian / Ubuntu Linux Settings File

Edit file /etc/network/interfaces. You can use GUI tool called network-admin to make and view changes :
network-admin
Here is sample wireless config file:
cat /etc/network/interfaces
Output:

auto lo
iface lo inet loopback
 
 
auto eth0
iface eth0 inet static
address 192.168.2.1
netmask 255.255.255.0
network 192.168.2.0
broadcast 192.168.2.255
 
auto wlan0
iface wlan0 inet dhcp
wpa-driver mrv8335
wpa-conf /etc/wpa_supplicant.conf