assign wifi device name to variable - macos

Question

I'm running the following command to figure out which network interface is being used currently.
networksetup -listallhardwareports | grep -C1 $(route get default | grep interface | awk '{print $2}')
How can I use that command and parse out the device name of that interface and then compare it to the device name of the Wi-Fi interface?
So I run the command above and this is what I get:
Hardware Port: Ethernet
Device: en0
Ethernet Address: a8:60:b6:03:0a:97
This is telling me that my ethernet port, or device en0 is the active network port on my computer. I want to assign en0 to a variable, say currentPort.
I will also run this command:
networksetup -listallhardwareports
This would be the results of that:
Hardware Port: Ethernet
Device: en0
Ethernet Address: a8:60:xx:xx:xx:xx
Hardware Port: Wi-Fi
Device: en1
Ethernet Address: 2c:f0:xx:xx:xx:xx
From this I want to pull the device name for my wifi, in this case en1 and assign it to another variable, say wifiPort.
So I should have currentPort=en0 and wifiPort=en1. I am hoping that I can then run an if then command that says is currentPort is not the same as wifiPort do one thing, if currentPort is the same as wifiPort, do something else.
Hope this helps explain things a little better.
This is what I'm working with right now, based on your help. echo $currentport and echo $wifiport doesn't give me any output and with the if commands, it echos "They are the same" regardless of what device I'm using.
#!/bin/bash
#currentport=`grep -A3 'Ethernet' t6.txt | grep "Device"| awk -F": " '{print $2}'`
currentport=`echo $a|grep -A3 'Ethernet'| grep "Device"| awk -F": " '{print $2}'`
echo $currentport
#wifiport=`grep -A3 'Wi-Fi' t5.txt | grep "Device"| awk -F": " '{print $2}'`
wifiport=`echo $b|grep -A3 'Wi-Fi'| grep "Device"| awk -F": " '{print $2}'`
echo $wifiport
if [[ $currentport == $wifiport ]]
then
echo They are the same
else
echo They are different
fi
exit 0

Answer 1

Try this:
For currentport:
Assume the output of your networksetup command is stored in a file: t6.txt
Hardware Port: Ethernet
Device: en0
Ethernet Address: a8:60:b6:03:0a:97
Do this:
mayankp#mayank:~/ currentport=`echo $a|grep -A3 'Ethernet'| grep "Device"| awk -F": " '{print $2}'`
mayankp#mayank:~/ echo $currentport
en0
For wifiport:
Assume the output of your networksetup command is stored in a file: t5.txt
Hardware Port: Ethernet
Device: en0
Ethernet Address: a8:60:xx:xx:xx:xx
Hardware Port: Wi-Fi
Device: en1
Ethernet Address: 2c:f0:xx:xx:xx:xx
Do this:
mayankp#mayank:~/ wifiport=`echo $b|grep -A3 'Wi-Fi'| grep "Device"| awk -F": " '{print $2}'`
mayankp#mayank:~/ echo $wifiport
en1
Now, you have both variables: $currentport and $wifiport.
Use if to do what you want:
if [[ $currentport == $wifiport ]]
then
<do your stuff>
else
<do other stuff>
fi
Let me know if this helps.

Answer 2

I think I'd avoid using all those pipes, and just do this in awk:
awk 'NR==FNR&&/interface/{i=$2} NR==FNR{next} index($0,"Device: "i)' \
<(route get default) \
RS= \
<(networksetup -listallhardwareports)
The awk script first parses the route command's output to determine the interface to use, then sets RS= which forces awk into multi-line mode, which allows the index() command to be used as a condition for printing a record.
And if you want just the WiFi port, the awk script is even simpler, because you don't need to parse the route command:
awk 'index($0,"Hardware Port: Wi-Fi")' RS= <(networksetup -listallhardwareports)
And if you want to compare the results, i.e. determine whether you are currently using WiFi, it's easy enough to wrap the commands you need in process substitution.
#!/bin/bash
currentPort=$(
awk '/interface/{print $2;exit}' <(route get default)
)
wifiPort=$(
awk 'index($0,"Hardware Port: Wi-Fi") {
sub(/.*Device: /,"");sub(/[[:space:]].*/,"")
print; exit
}' \
RS= \
<(networksetup -listallhardwareports)
)
if [[ "$wifiPort" = "$currentPort" ]]; then
echo "I'm on WiFi!"
else
echo "I'm NOT on WiFi!"
fi
Of course, you could also do this in bash alone, without the need for awk:
#!/bin/bash
junk=$(route get default)
[[ $junk =~ .*interface:\ ([a-z]+[0-9]+) ]]
currentPort="${BASH_REMATCH[1]}"
while read line; do
if [[ $line = *Wi-Fi ]]; then
read line
wifiPort="${line##* }"
break
fi
done < <(networksetup -listallhardwareports)
if [[ "$wifiPort" = "$currentPort" ]]; then
echo "I'm on WiFi!"
else
echo "I'm NOT on WiFi!"
fi
Note that the while read line loop isn't particularly efficient, and a bash 4 mapfile/readarray would perform better. But the default version of bash in macOS is still 3. :)