If you are using kernel 4.0 or above, the module should come together with the kernel. You can identify below and you plug the device into the usb port.
root@localhost:~# modinfo r8188eu
filename: /lib/modules/4.0.0-2-amd64/kernel/drivers/staging/rtl8188eu/r8188eu.ko
version: v4.1.4_6773.20130222
author: Realtek Semiconductor Corp.
description: Realtek Wireless Lan Driver
license: GPL
srcversion: A3DA328AE8853D31D90212F
alias: usb:v0DF6p0076d*dc*dsc*dp*ic*isc*ip*in*
alias: usb:v2001p3311d*dc*dsc*dp*ic*isc*ip*in*
alias: usb:v2001p3310d*dc*dsc*dp*ic*isc*ip*in*
alias: usb:v2001p330Fd*dc*dsc*dp*ic*isc*ip*in*
alias: usb:v07B8p8179d*dc*dsc*dp*ic*isc*ip*in*
alias: usb:v056Ep4008d*dc*dsc*dp*ic*isc*ip*in*
alias: usb:v0BDAp0179d*dc*dsc*dp*ic*isc*ip*in*
alias: usb:v0BDAp8179d*dc*dsc*dp*ic*isc*ip*in*
depends: usbcore
staging: Y
intree: Y
vermagic: 4.0.0-2-amd64 SMP mod_unload modversions
parm: rtw_ips_mode:The default IPS mode (int)
parm: ifname:The default name to allocate for first interface (charp)
parm: if2name:The default name to allocate for second interface (charp)
parm: rtw_initmac:charp
parm: rtw_channel_plan:int
parm: rtw_chip_version:int
parm: rtw_rfintfs:int
parm: rtw_lbkmode:int
parm: rtw_network_mode:int
parm: rtw_channel:int
parm: rtw_wmm_enable:int
parm: rtw_vrtl_carrier_sense:int
parm: rtw_vcs_type:int
parm: rtw_busy_thresh:int
parm: rtw_ht_enable:int
parm: rtw_cbw40_enable:int
parm: rtw_ampdu_enable:int
parm: rtw_rx_stbc:int
parm: rtw_ampdu_amsdu:int
parm: rtw_lowrate_two_xmit:int
parm: rtw_rf_config:int
parm: rtw_power_mgnt:int
parm: rtw_smart_ps:int
parm: rtw_low_power:int
parm: rtw_wifi_spec:int
parm: rtw_antdiv_cfg:int
parm: rtw_antdiv_type:int
parm: rtw_enusbss:int
parm: rtw_hwpdn_mode:int
parm: rtw_hwpwrp_detect:int
parm: rtw_hw_wps_pbc:int
parm: rtw_max_roaming_times:The max roaming times to try (uint)
parm: rtw_fw_iol:FW IOL (int)
parm: rtw_mc2u_disable:int
parm: rtw_80211d:Enable 802.11d mechanism (int)
parm: rtw_notch_filter:0:Disable, 1:Enable, 2:Enable only for P2P (uint)
parm: debug:Set debug level (1-9) (default 1) (int)
root@localhost:~# dpkg -S /lib/modules/4.0.0-2-amd64/kernel/drivers/staging/rtl8188eu/r8188eu.ko
linux-image-4.0.0-2-amd64: /lib/modules/4.0.0-2-amd64/kernel/drivers/staging/rtl8188eu/r8188eu.ko
If you get the following message in your syslog,
Sep 1 19:12:33 localhost kernel: [ 385.525522] r8188eu 1-1.1.2.3:1.0: firmware: failed to load rtlwifi/rtl8188eufw.bin (-2)
Sep 1 19:12:33 localhost kernel: [ 385.525530] r8188eu 1-1.1.2.3:1.0: Direct firmware load for rtlwifi/rtl8188eufw.bin failed with error -2
Sep 1 19:12:33 localhost kernel: [ 385.525534] r8188eu 1-1.1.2.3:1.0: Firmware rtlwifi/rtl8188eufw.bin not available
Sep 1 19:12:33 localhost kernel: [ 385.525539] MAC Address = 00:00:00:00:00:00
What you need to do next is to install the firmware. The firmware is in the repository and you can install as easy as apt-get.
root@localhost:~# apt-get install firmware-realtek
Now the userspace application should be able to identify the device correctly. I am using gnome so, it is detected as USB Wi-FI. Note that I have an existing pci wifi as shown in the screenshot below.
Try out to device to retrieve the IP address etc. If you get your wireless to a funky name such as wlxc412f52da87d , then you can create a rule in the udev configuration file.
# cat /etc/udev/rules.d/70-persistent-net.rules
# This file was automatically generated by the /lib/udev/write_net_rules
# program, run by the persistent-net-generator.rules rules file.
#
# You can modify it, as long as you keep each rule on a single
# line, and change only the value of the NAME= key.
# PCI device 0x0000:0x0000 (atl1c)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:00:00:00:00:00", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth0"
# PCI device 0x0000:0x0000 (brcm80211)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:00:00:00:00:0", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="wlan*", NAME="wlan0"
# USB device 0x0000:0x0000 (r8188eu)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:00:00:00:00:00", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="wlan*", NAME="wlan1"
As you can see above, PCI device my existing device and you should add another line similar to the above. You need to replace ATTR{address} value to your device mac address. When the operating system bring up this device, it will be renamed to wlan1 instead of a random interface name next time.
