RHEL AUDITD
Environment Red Hat Enterprise Linux (RHEL) 4 5 6 7 Issue How to monitor the permission change and ownership change […]
Linux
VI Editor cheat sheet
vi mode commands Command Action k Move one line upwards l Move one character to the right h Move one […]
HAProxy + Keepalived on AlmaLinux 9 and RHEL 9: A Two-Node HA Load Balancer
Updated for 2026: the original build ran on CentOS 7 / RHEL 7, both end-of-life (CentOS 7 died in June […]
Linux Multiple Gateways
example use: one gateway to send outgoing traffic. Other traffic use the other gateway. Two Gateways below for example: gw1 […]
Digital Black Hole /dev/null
root@anywhere: ~/void root@anywhere:~# ls -l /dev/null # crw-rw-rw- 1, 3 — a character device, not a file Digital Black Hole […]
NMAP – scan for unused or down IP’s
nmap -v sn -n 192.168.3.0/23 -oG – | awk ‘/Status: Down/{print $2}’ -sn (No port scan) . This option tells […]