In the C and TC shell, to show the values of all your environment variables:
printenv TERM=vt100 HOME=/home/eucs/helper SHELL=/usr/local/bin/Tcsh USER=helper TZ=GMT0BST UCBPATH=:/usr/ucb:/bin:/usr/bin ATTPATH=:/bin:/usr/bin UCBSHELL=/usr/local/bin/Tcsh ATTSHELL=/bin/sh LOGNAME=helper MAIL=/home/eucs/helper/.mail
This shows that this user's terminal type is set to VT100, that they use the TC shell and that they are on Greenwich Mean Time.
In the Bourne, BASH and Korn shell, to show the value of all your variables:
set BASH=/usr/local/utils/bin/bash BASH_VERSION=1.12.1 DELIVERY=John Smith Room 2004 JCMB DISPLAY=frolix8.ucs:0 EDITOR=ue FOLDERS=/home/eucs/erpl08/Mail HISTFILE=/home/eucs/erpl08/.bash_history HISTFILESIZE=50 HISTSIZE=100 HOME=/home/eucs/erpl08
...
This shows the value of an assorted range of variables.