Question

Create files with the following names : test1, test2, test3. Create a symbolic link to test2 and name it test4 Create a directory and name it test5.

Write a shell script to perform the following tasks:

• check if a file named test6 exist. If not, it should create it.

• Display a text to indicate whether test4 is symbolic link or not

• Display a text to indicate whether test2 is directory or not

• Display a text to indicate whether test1 is older than test4

• Display a text to indicate whether tes3 is a character device file or not.

Answer 1

To create the 3 files, we use the touch command as:

touch test1

Then we create the symbolic link using ln command:

ln -s test2 test4

Finally we create directory by:

mkdir test5

Now, we have the following structure before our script:

We have written the following script in script.sh :

SCRIPT:

FILE=test6
#To check if file exists, we use the -f operator
if [ -f "$FILE" ]; then
echo "$FILE exists."
else
echo "$FILE does not exist, creating it."
touch $FILE
fi
#To check if file is a symbolic link & it exists, we use the -L operator
FILE=test4
if [ -L "$FILE" ]; then
echo "$FILE is a symbolic link."
else
echo "$FILE is not a symbolic link."
fi

FILE=test2
if [ -d "$FILE" ]; then
echo "$FILE is a directory."
else
echo "$FILE is not a directory."
fi
# The -ot operator compares if first file is older than the second file specified
if [ "test1" -ot "test4" ]
then
echo "test1 is older than test4."
else
echo "test1 is not older than test4."
fi

FILE=test3
if [ -c "$FILE" ]; then
echo "$FILE is a character device file."
else
echo "$FILE is not a character device file."
fi

Script Output:

(*Note: Please up-vote. If any doubt, please let me know in the comments)