# As I just mentioned, there are 2 types of variables floating
# around in UNIX.  The other are the «environment», a set of
# variables passed around to each program. In a short while, we will
# write a C program to look at them, so you see that they are not
# the same as shell variables.

# In any case, the program ‹env› prints all environment variables.
# You can run it like this:

echo '# looking for PATH in the environment'
env | fgrep PATH

# Shells typically make it possible to add their own variables into
# the environment, and they make all environment variables available
# as their own (via ‹$› expansion).

echo '# doing echo $PATH'
echo $PATH

# Adding variables into the environment is done with ‹export›:

echo
echo '# setting VAR, echo-ing it and looking for it in env'
VAR=17
echo $VAR
env | fgrep VAR

echo
echo '# exporting VAR, echo-ing it and looking for it in env'
export VAR
echo $VAR
env | fgrep VAR

echo
echo '# changing the value of VAR'
VAR=13
echo $VAR
env | fgrep VAR

echo
echo 'That said, let us go on to getenv.c'