Operating System : RHEL 5.x,6.x&7.x,
Servers : FTP, NFS, SAMBA, DHCP, DNS, APACHE, TOMCAT, Mail server
Backup : Tar, Rsync, Scp, Zip
Database : MySQL
Package Management: RPM and YUM, several command options for rpm
Monitoring Tools : Nagios, Sensu, Icinga,
Scripting : Shell Script
Virtualization : VMware5.x,6.x,Vcenter,Vsphere
Cloud : AWS