#!/usr/bin/perl 
# This perl script sets the shell environment variable with $ENV{BB},
# then runs some Unix commands with back-quotes and \$BB .
#
# This script outputs,
#    Shell environment variable BB has been changed to: /var/log 
#    One directory back, via back-quotes is: /var


# The following makes available the environment variable $CC .
printf "The current environment variable \$CC is:  %s\n", $ENV{CC} ;

$ENV{BB}="/var/log" ;	#CHANGE ENVIRONMENT.
printf "Shell environment variable \$BB has been changed to: %s \n", $ENV{BB} ;

# In the following, note  \$BB  so $ gets interpreted 
# by the shell (in backquotes) rather than by perl.
printf `cd \$BB;   cd ..;   echo -n "One directory back, via back-quotes is: ";    pwd ` ;