The contents of environment variables can be made visible with the echo command. To get the value, the name of the environment variable must be preceeded by a $-sign:
echo $PRINTER
513-pub
The value for PRINTER is shown.
If you forget the $-sign, the character string is printed and not its value:
echo PRINTER
PRINTER
Again you should keep in mind that Unix is case sensitive. This means that
environment variables such as printer, Printer and PRINTER
are all different.
A More Advanced Example
For example, if you want to have your current host name and current working directory named MyEnv, using the Bourne Shell you can proceed as follows:
NODE=`hostname`; export NODE
MyEnv=$NODE:$PWD; export MyEnv
echo 'My Environment: $MyEnv'
My environment: rzri6f:/u/goeri
With the first statement, a new global variable NODE is defined. NODE gets the
output of the command hostname as value, which is achieved by enclosing the
command name in single backquotes. Then the values of NODE and of the
environment variable PWD, which is already provided by the system and contains
always the current working directory, are put together in MyEnv. Finally,
to control the success of this action, the contents of MyEnv is printed to
your terminal window, prefixed by some text.