Question

Write a short bash program that aligns with the below functionality.

$ sh ~/cs210_list.sh Error: missing argument $ echo $? 1 $ sh ~/cs210_list.sh /non-exist Error: ‘/non-exist’ is an invalid directory $ echo $? 1 $ sh ~/cs210_list.sh /etc File: aavark File: aabbb Size: 16 File: aaacccc File: aaaaddd Size: 1585 File: aliases~ Size: 1686 File: aliases.db Size: 12288 ...

Notice:

• It error checks that the first argument exists and is a directory.
• It generates an error message and returns a failure code in error situations.
• It only outputs a file size when the item is a file (and not the name of a directory).

Grading Criteria:

In my check, I will ask you to do the following checks:

• If the script has no arguments, it should:
  • Print the following: "Error: missing argument". (5pts)
  • Generate error code 1; Check this by doing the command "echo $?" right afterwards. (5pts)
• If the script is given an argument that points to an invalid directory (example: the /non-exist directory), then your code should:
  • Print the following: " Error: ‘<insert argument here>’ is an invalid directory". Don't forget to print out the provided argument. (5pts)
  • Generate error code 1; Check this by doing the command "echo $?" right afterwards. (5pts)
• Otherwise, if the directory is normal, it should run just like the question titled "Exercise: a simple loop".
  • In short, it should print the name (5pts) and size (5pts) of each file in the directory, in the exact format like above and the prior question.

Copy and paste your program below

Answer 1

i) # Shell script for missing argument

 if [ $# -eq 0 ]

then

echo " Error: Missing argument"

else

echo " There are $# arguments and they are:  $* "

fi

*************************************************

# Script to pass an arument through command line and check whether it is a valid directory or not

if [ $# -eq 0 ] # $# always holds the number of arguments passed, this checks for arguments absence

then

echo " No arguments are passed"

elif [ $# -eq 1 -a -d $1 ] # This checks for 1 argument and must be a valid directory.

then

echo "It is a valid directory"

else

echo "It is not a directory"

fi

**************************************************

iii)

Note : I am considering the argument passed is a directory and it will print only the ordinary file name along with it size.

# Script to display the name of a file along with its size

if [ $# -eq 0 ]

then

echo " Pass a valid directory as an argument .........."

elif [ $# -eq 1 -a -d $1 ]

then

ls -lR $1 | tr -s ' ' | cut -d ' ' -f 9 > a

ls -lR $1 | tr -s ' ' | cut -d ' ' -f 5 > b

paste a b

fi

Note : $? is a special parameter used to check exit status of a command ...