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I need to loop over the network interfaces available in Linux. I'm interested in all kinds of interfaces (loopback, ethernet, vlan, bridge) - whatever shows up in ifconfig -a.

Is there a way to enumerate the interfaces in Linux? By any command or by reading a file?

mattdm
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user1762571
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    Well this works... ifconfig -a | grep 'flags' | wc -l – orion Jul 02 '15 at 20:18
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    @orion, I would recommend using ip instead as it is a successor of ifconfig - ip -o link show | wc -l. See this question – VL-80 Jul 02 '15 at 23:54
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    You might look at netdevice(7)). – o11c Jul 03 '15 at 02:15
  • @Nikolay of course, that's what I would use, and others already posted that answer (and removed it). I just wanted to point out that from what OP did to the answer to his question isn't very far. – orion Jul 03 '15 at 06:39
  • Just in case it helps anyone, adding the option "1" to the ls command will list output one item per line, e.g: ls -A1 /sys/class/net eth0 lo usb0 wlan0 In fact, I was surprised to find the count using "wc -l" still works on the single line version of the command (ls -A). But there are likely other situations where the item-per-line output from ls will be preferable, or necessary. – Alex Apr 24 '17 at 01:52

1 Answers1

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You can get a list of these interfaces on most systems from the following:

ls -A /sys/class/net

But beware of parsing the output from ls in your script.

Edit

To get a total number of network interfaces pipe the output of this command into wc as recommended in Nikolay's comment as in:

ls -A /sys/class/net | wc -l
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