LAB EXERCISE $2$

You are now going to modify the script you write for Lab Exercise $1$D to see if a master file exists and, if it doesn't, create one. Then, in the loop, you will ignore any non$-$regular files and the master file.

A$.$ At the beginning of the script, add a line that defines a variable called MASTER, and give it the initial value "MasterList". Call this script $"$

scan$2$a$.$py$".$ When you are done, save a copy because you will use this in Lab Exercise $3.$

$.$ After the variable definition but before your loop, test to see if the file named by the value of the variable MASTER exists. If so$,$ print the message that the file "exists; please delete it$"$ and exit, giving exit status code $1.$ If not, create it$.$ Call this script $"$

scan$2$b$.$py$".$

c$.$ In the for loop, before you print the file attributes, check to see if the file being examined is either a regular file or the MasterList file. If it is neither, immediately go to the next file $($that is$,$ do not get the file attributes$).$ Call this script $"$

scan$2$c$.$py$".$

d$.$ Modify your script so that the attributes are stored in the file named by the value of the variable MASTER. Call this script $"$

scan$2$d$.$py$".$

E$.$ Finally, if everything works, have the script exit with an exit status code of $0.$ Call this script $"$

scan$2$e$.$py$".$

Run your script. There should be no output. Then look for a file called MasterList and compare its contents to what you got for the output of

script$1.$sh$.$ The outputs for the files abc xyz$,$ abcde,

demo.for.sh$,$

demofor$2.$sh$,$ and demofor$3$sh should be the same. The other files that are present should all be ones you created or put there.