By default ifconfig will show me all available interfaces , but what if I just want to display active ones? Like, en0 only in below.
en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
ether 14:10:9f:e0:eb:c9
inet6 fe80::1610:9fff:fee0:ebc9%en0 prefixlen 64 scopeid 0x4
inet X.X.X.X netmask 0xffffff00 broadcast 101.6.69.255
nd6 options=1<PERFORMNUD>
media: autoselect
**status: active**
en3: flags=8963<UP,BROADCAST,SMART,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
options=60<TSO4,TSO6>
ether 32:00:14:e7:4f:80
media: autoselect <full-duplex>
**status: inactive**
Notice ifconfig en0 will not satisfy, en0 is not always the active one 😉
I’m running Mac OS X.
Answers:
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Method 1
To get a complete description of all the active services, try:
ifconfig | pcregrep -M -o '^[^t:]+:([^n]|nt)*status: active'
This simple regex should filter out only active interfaces and all their information. I sugest you put an alias for this in your ~/.profile or ~/.bash_profile file (maybe ifactive?)
To just get the interface name (useful for scripts), use:
ifconfig | pcregrep -M -o '^[^t:]+:([^n]|nt)*status: active' | egrep -o -m 1 '^[^t:]+'
You have to install pcregrep for this to work. It’s on macports in the pcre package. Alternatively, this should work with GNU grep using grep -Pzo instead of pcregrep -M -o but with the rest the same, but I haven’t tested this.
Method 2
If you are not adverse to some bash scripting, you can do this:
for i in $(ifconfig -lu); do if ifconfig $i | grep -q "status: active" ; then echo $i; fi; done
That’s will list out the active network interfaces. Tested on Mac OS X 10.13.
The nice thing is that you don’t need to install anything. Just run the above in a Terminal.
Method 3
If you only want to print the “entry” if it contains status: active, then you could use something like this awk program as a filter to the ifconfig output:
#!/usr/bin/awk -f
BEGIN { print_it = 0 }
/status: active/ { print_it = 1 }
/^($|[^t])/ { if(print_it) print buffer; buffer = $0; print_it = 0 }
/^t/ { buffer = buffer "n" $0 }
END { if(print_it) print buffer }
When each “entry” starts (a line is empty or does not start with a Tab), start saving the entry in a buffer. Append to this buffer any subsequent lines that start with a Tab. Watch for the magic string status: active; if a line like that was seen, print out the buffer (the previous “entry”) when a new “entry” starts (or the input ends).
Save the above program text in a file and use it like this:
ifconfig -a | awk -f /path/to/file
Or, if you chmod +x the file, then you can simplify it a bit:
ifconfig -a | /path/to/file
Method 4
Reading your comments and question, it seems you actually want to just get the interfaces that have an IP address assigned to them.
You can do this quickly with ifconfig and grep.
Running the command:
ifconfig | grep 'Link|inet'
Should produce something similar to:
eth0 Link encap:Ethernet HWaddr 00:11:22:33:44:55
eth1 Link encap:Ethernet HWaddr 00:11:22:33:44:66
inet addr:192.168.0.8 Bcast:192.168.0.255 Mask:255.255.255.0
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
This would show each line with a interface name and and IP if they had one.
Some more specific REGEX magic might get you exactly what you need.
Method 5
Following will print out only those interfaces that are configured to have an IP
ifconfig | grep "inet.*broadcast"
Method 6
I wish the question was a bit clearer. Assuming that by Active interface only, you meant to show the name of active interfaces only (In my case UP and RUNNING status active) without any other details. Then try this:
ifconfig |
grep "UP|RUNNIG"
| awk '{print $1}'
| grep ':'
| tr -d ':'
| grep -v lo
The output would look like:
en0 en1 en2 bridge0 p2p0 awdl0 llw0 utun0 utun1 utun2 utun3 en6
Adjust the grep -v field and add in more unwanted interfaces like loopback –> lo etc, if necessary.
Now, if you want and you would need to check whether the interfaces found are active at present. Then we can just simply pass them as an argument for ifconfig <interface> like shown below:
[[ $(ifconfig en0 | grep -w active) ]] && echo "en0 is active"
Simplifying this further and implementing it in a function:
checkActiveInterfaces()
{
local intARR=( $(ifconfig |
grep "UP|RUNNIG"
| awk '{print $1}'
| grep ':'
| tr -d ':'
| grep -v lo) );
intARR=( $(printf "%sn" "${intARR[@]}" | sort -u) );
for i in "${intARR[@]}"; do
[[ $(ifconfig $i | grep -w active) ]] && {
echo "$i"
}
done
}
Executing this function will return only the active interfaces. In my case:
awdl0 en0 llw0
Method 7
I had to do this recently where it wasn’t known if eth0 or eth1 would be up, but the system does not have pcregrep.
Here was my solution:
for interface in /sys/class/net/*; do [ `cat $interface/operstate` == "up" ] && ifconfig `basename $interface`; done
operstate gets checked first, and if it matches up then run ifconfig on it.
Method 8
Get ACTIVE interface MAC only:
cat /sys/class/net/$(ip addr | awk '/state UP/ {print $2}' | sed 's/.$//')/address
Method 9
netstat -i will show you a list of all active interfaces, networks, addresses (ip4, ip6, MAC), and a few more columns of stats on macOS versions ranging from High Sierra (10.13) to Monterey (12.3) (the 2 systems I have easy access to).
% netstat -i Name Mtu Network Address Ipkts Ierrs Opkts Oerrs Coll lo0 16384 <Link#1> 7680002 0 7680002 0 0 lo0 16384 127 localhost 7680002 - 7680002 - - lo0 16384 localhost ::1 7680002 - 7680002 - - lo0 16384 mac-manager fe80:1::1 7680002 - 7680002 - - en0 1500 <Link#6> a4:83:e7:73:2b:b8 4393235 0 2854958 0 0 en0 1500 mac-manager fe80:6::1479:f3f9 4393235 - 2854958 - - en0 1500 192.168.162 192.168.162.196 4393235 - 2854958 - - en1 1500 <Link#7> 82:98:60:06:e0:01 0 0 0 0 0 en2 1500 <Link#8> 82:98:60:06:e0:00 0 0 0 0 0 : : llw0 1500 fe80::6c3f: fe80:b::6c3f:2fff 0 - 0 - - utun0 1380 <Link#12> 0 0 2 0 0 utun0 1380 mac-manager fe80:c::8eb3:ce45 0 - 2 - - : : utun10 1380 <Link#26> 0 0 3 0 0 utun10 1380 mac-manager fe80:1a::7e37:30c 0 - 3 - - en4 1500 <Link#22> 00:50:b6:9b:20:7a 178041 0 8093 0 0 en4 1500 mac-manager fe80:16::106d:4e6 178041 - 8093 - - en4 1500 10.1.2/24 macmanager.myne 178041 - 8093 - -
Method 10
$ ifconfig | grep "inet addr:" | grep -v 127.0.0.1 | sed -e 's/Bcast//' | cut -d: -f2
How it works:
- ifconfig
- Grep for lines containing “inet addr”
- These lines contains the IPs.
- Grep for lines that do not contain “127.0.0.1”
- We usually do not care about localhost.
- -v is inverted grep
- From remaining lines, remove the “Bcast”
- Cut field 2 using “:” as a delimiter
- Prints the answer.
All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0