List Network Adaptors
ifconfigIs Network Interface Connected
cat /sys/class/net/wlan0/operstateIndicates the interface operational state, possible values are: “unknown”, “notpresent”, “down”, “lowerlayerdown”, “testing”,”dormant”, “up”.”no such file or directory”
You can test for “up”.
cat /sys/class/net/wlan0/carrierWill give a result of 0, 1 or a ‘no such file or directory’ error message.
NOTE – we have seen this commant return a ‘1’ when the WiFi adaptor is not actually connected (‘ip addr’ returns “wlan0: <NO-CARRIER,…”. In this instance cat /sys/class/net/wlan0/operstate returned “dormant”
Other commands
See https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-class-net
Restarting After Changes
See here.
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