Using option --by-interface with a non-existent network interface name
results in an unexpected duplicate warning message:
$ lszdev --by-interface xx
Could not open directory /sys/class/net/xx: No such file or directory
Could not open directory /sys/class/net/xx: No such file or directory
lszdev: Could not determine device that provides xx (xx)
Fix this by checking for the existence of the associated /sys/class/net
directory before initiating the associated directory traversal.
Reviewed-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Signed-off-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>