:
# list the process ID number 
echo The process id number is: $$

# store the process ID number in a variable and display it
fname=$$
echo The process id number is: $fname

# create a unique file name using the Process ID number
fname2=/tmp/spy$$
echo A unique filename using the process ID number is: $fname2

# store information into the file
w > $fname2
echo Listing of contents of $fname2
more $fname2

# remove the temp file
rm $fname2