Shell Scripts

#!/bin/csh

if ($#argv != 1) then
    echo "Wrong number of arguments"
else 
    if (-d $1) then
        cd $1
        echo "---- Start of directory $1"
        foreach Name (*)
            if (-d $Name) then
                summary $Name
            else
                wc $Name # >> lst.sum
                endif
            end
        echo "---- End of directory $1"
    else 
        echo "Invalid directory name: $1"
        endif
    endif

1. Explain what shell scripts are.
2. Explain how the shell script can be executed. (Hint: there are 2 ways)
3. Create a new directory under your cp1300 directory, called "test". Inside "test" create two sub-directories "sub1" and "sub2". Place some text files inside "test", "sub1", and "sub2".
4. Change into ~/cp1300/test/ and make a copy of summary inside "test" (You can make it executable if you wish).
5. Once you get it working, analyse the shell script summary (try and use it like this: summary ./), and describe what it is doing.

   Note: As it is written above, summary will not work properly. What is causing the problem? And what can be done about it?

6. Construct your own shell script, call it unsummary which takes a single argument (a directory name) and proceeds to display the contents of the lst.sum files that were created.
7. Modify your unsummary script so that all of the lst.sum files are removed instead of them being displayed.

   Note: be VERY careful using the rm command. Because once something is removed, it is not trivial to restore it! Don't try this question until you complete the previous version of unsummary.