That's the form from the usage screen:
$ wpa_supplicant
Successfully initialized wpa_supplicant
wpa_supplicant v2.9
Copyright (c) 2003-2019, Jouni Malinen <[email protected]> and contributors
This software may be distributed under the terms of the BSD license.
See README for more details.
This product includes software developed by the OpenSSL Project
for use in the OpenSSL Toolkit (http://www.openssl.org/)
usage:
wpa_supplicant [-BddhKLqqstuvW] [-P<pid file>] [-g<global ctrl>] \
[-G<group>] \
-i<ifname> -c<config file> [-C<ctrl>] [-D<driver>] [-p<driver_param>] \
[-b<br_ifname>] [-e<entropy file>] [-f<debug file>] \
[-o<override driver>] [-O<override ctrl>] \
[-N -i<ifname> -c<conf> [-C<ctrl>] [-D<driver>] \
[-m<P2P Device config file>] \
[-p<driver_param>] [-b<br_ifname>] [-I<config file>] ...]
drivers:
nl80211 = Linux nl80211/cfg80211
wext = Linux wireless extensions (generic)
wired = Wired Ethernet driver
macsec_linux = MACsec Ethernet driver for Linux
none = no driver (RADIUS server/WPS ER)
options:
-b = optional bridge interface name
-B = run daemon in the background
-c = Configuration file
-C = ctrl_interface parameter (only used if -c is not)
-d = increase debugging verbosity (-dd even more)
-D = driver name (can be multiple drivers: nl80211,wext)
-e = entropy file
-f = log output to debug file instead of stdout
-g = global ctrl_interface
-G = global ctrl_interface group
-h = show this help text
-i = interface name
-I = additional configuration file
-K = include keys (passwords, etc.) in debug output
-L = show license (BSD)
-m = Configuration file for the P2P Device interface
-N = start describing new interface
-o = override driver parameter for new interfaces
-O = override ctrl_interface parameter for new interfaces
-p = driver parameters
-P = PID file
-q = decrease debugging verbosity (-qq even less)
-s = log output to syslog instead of stdout
-t = include timestamp in debug messages
-T = record to Linux tracing in addition to logging
(records all messages regardless of debug verbosity)
-u = enable DBus control interface
-v = show version
-W = wait for a control interface monitor before starting
example:
wpa_supplicant -Dnl80211 -iwlan0 -c/etc/wpa_supplicant.conf
I tried both forms, and both seem to work:
# wpa_supplicant -i wlan0 -D nl80211 -c /etc/wpa_supplicant/wpa_setnet.conf
and
# wpa_supplicant -iwlan0 -Dnl80211 -c/etc/wpa_supplicant/wpa_setnet.conf