If you want to configure WLAN settings on a Linux machine statically you can use the normal /etc/network/interfaces configuration method of Debian. For WPA-PSK you can use this 3 steps:
Install the “wpasupplicant” package
Generate a psk line with “wpa_passphrase” and copy the hex string after “psk=”
root@server:~# wpa_passphrase WLANNAME
# reading passphrase from stdin
thepassword
network={
ssid="WLANNAME"
#psk="thepassword"
psk=fe5409c4831b3daafff41fe2e6ed15ba7ed18c87bab254315e0be5f9180573d3
}
Add some lines to /etc/network/interfaces using this hex string
allow-hotplug wlan0
iface wlan0 inet dhcp
metric 4
wpa-essid WLANNAME
wpa-scan-ssid 1
wpa-psk fe5409c4831b3daafff41fe2e6ed15ba7ed18c87bab254315e0be5f9180573d3
The line “wpa-scan-ssid 1” allows to use hidden WLAN that are not broadcasted. With “metric 4” you can make WLAN less preferred if there is a second LAN connection that should be preferred (default is “metric 1”).