Linux - System config & hardware info

Current Language:
$ set | egrep '^(LANG|LC_)'

Installed device drivers (modules)
$ lsmod

Information about an X server:
$ xdpyinfo

User shell name:
$ ps -p $$ | tail -1 | awk '{ print $4 }'

Dump Linux kernel variables
$ /sbin/sysctl -a

Running Linux kernel version:
$ uname -mrs
$ uname -a
$ cat /proc/version

Display list of all open ports
$ netstat -tulpn