I want to check only the network interfaces status on the server which is listed in the command output on linux bash

Question

I want to get the output only the interface which is down based on the configured interfaces in the network-scripts directory.

for i in $(ls -1 /etc/sysconfig/network-scripts/ifcfg-e*|sed 's/.*ifcfg-//g'); do grep -i 'down' /sys/class/net/$i/operstate; echo $i;done

How can I list only the interfaces which is down based on the input of the for iteration?

Thank you

Answer 1

I suggest with bash, its Parameter Expansion and CentOS 7 / RHEL 7:

for i in /etc/sysconfig/network-scripts/ifcfg-e*; do 
  i=$(basename "$i")
  grep -qi 'down' "/sys/class/net/${i#*-}/operstate" && echo "${i#*-}"
done

${i#*-} removes from string ifcfg-ens33 ifcfg- to get only interface name.

Update:

for i in /etc/sysconfig/network-scripts/ifcfg-e*; do
  grep -qi 'down' "/sys/class/net/${i##*-}/operstate" && echo "${i##*-}"
done

${i##*-} removes from string /etc/sysconfig/network-scripts/ifcfg-ens33 /etc/sysconfig/network-scripts/ifcfg- to get only interface name.