Some linux commands on troubleshooting

certs_management.sh

#Download certs from site
echo "" | openssl s_client -host {HOST} -port 443 -showcerts | awk '/BEGIN CERT/ {p=1} ; p==1; /END CERT/ {p=0}' > allcerts.pem

#Import certs
keytool -import -alias your-alias -keystore cacerts -file certificate.der

troubleshoothig.sh

#Release memory on Linux:
echo 3 > /proc/sys/vm/drop_caches

#Check IO usage on CPU:
iostat -x 2 5

#Check ports:
sudo lsof -i :5672 | grep LISTEN

#File max size
du -a /var | sort -n -r | head -n 10

# Check last reboots
who -b 
last reboot | less

# Check ports and linked processes
ss -l -p

# Filter traffic
tcpdump -i eth1 port XXXX -w file

# Check License
rpm -qa --queryformat '%{name},%{version},%{license}\n' | grep GPLv3