Linux Commands One Liner

List out multiple IPv4/v6 IPs assigned to the server

IPv4:

ip -4 a | grep global | sed 's/\/.*//g' | awk '{print $2}'

IPv6:

ip -6 a | grep global | sed 's/\/.*//g' | awk '{print $2}'

Assigning a subnet of IPs using Network Manager Command Line Interface (nmcli)

for I in $(seq 2 254); do nmcli con mod eth0 +ipv4.addresses 192.168.0.${I}; done

nmcli con up eth0

Convert unix time stamp to human readable time format for access log

perl -pe 's/([\d]{10})/localtime $1/eg;'

For example:

cat access.log | perl -pe 's/([\d]{10})/localtime $1/eg;'

Print only first three octets of IPv4 addresses from the list of IPs from the file

cat iplist.txt | cut -d '.' -f 1-3 | sort -n | uniq

Print lines from the access log files where nth column values are in the range specified

cat access.log | awk '$5 >= 1000000 && $5 < 2000000 {print ;}' 

Print lines from the access log file where nth column value exactly matches with the provided value

cat access.log | grep TCP_MISS | awk '$7 == 200  {print ;}'