Added environment variable and file handling to bash script example.

bash/hello.sh

@@ -5,11 +5,9 @@
 
 declare -a animals=("camel" "llama" "owl")
 declare -A FRUIT_COLOR
-
 FRUIT_COLOR=( ["apple"]="red" ["banana"]="yellow")
 VERINFO=`git describe --abbrev=7 --dirty --always --tags`
 
-
 # Obligatory Hello World with some version info
 echo "Hello Bash World!  Version: $VERINFO"
 
@@ -39,3 +37,45 @@ for fruit in "${!FRUIT_COLOR[@]}"; do
 	echo "$fruit = ${FRUIT_COLOR["$fruit"]}";
 done | sort --reverse
 
+# Read a non-existent environment variable and supply default value...
+SOME_ENV_VAR=${PROBABLY_NOT_THERE-Default Value}
+echo ""
+echo "PROBABLY_NOT_THERE is set to '$SOME_ENV_VAR'"
+echo ""
+
+# Let's read in the PATH variable from the OS and print it out...
+PATH_ENV_VAR=$PATH
+echo "OS PATH var is set to: '$PATH'"
+echo ""
+
+# Let's manipulate PATH variable and then restore it
+echo "Adding :/test to PATH variable"
+PATH=$PATH:/test
+echo "OS PATH var is set to: '$PATH'"
+echo ""
+echo "Restoring original PATH value."
+PATH=$PATH_ENV_VAR
+echo "OS PATH var is set to: '$PATH'"
+echo ""
+
+# Let's create the file test.out and write animals array to it...
+echo ""
+echo "Writing test.out file..."
+rm -f test.out
+for i in ${animals[@]}
+do 
+	echo $i >> test.out
+done
+
+# Now open the file we wrote and read it back...
+echo ""
+echo "Contents of test.out file:"
+LINECOUNT=1
+while read line
+do
+	echo "line $LINECOUNT: $line"
+	LINECOUNT=$[$LINECOUNT +1]
+done <test.out
+
+# All done, finish with normal exit code.
+exit 0