Bash a script that downloads and reports upon all of a user-specified image type, e.g. png, jpg, jpeg, gif, at a
user-provided URL.
Required Script Functionality
▪ The user is to be prompted for the desired URL and image type
▪ Your assessor will always enter a valid URL, so you don’t need to validate for this
▪ Your script is to scan for and download images of the following four (4) types only:
1. .jpg
2. .jpeg
3. .gif
4. .png
▪ Keep in mind that URLs often contain multiple copies of the same image file, hyperlinked in different
locations on the page users interact with, therefore, your code will need to account for this so that
such duplicates, where they exist, are neither downloaded nor displayed in the final summary or any
of its statistics
▪ URLs that contain no image files of the allowed types will also be used during the assessment
process, so your script will need to allow for this scenario as well, informing the user of this with an
appropriate terminal message when it occurs and exiting the script exited gracefully
▪ In the event that allowable image file(s) of the type the user stipulates are available at the URL
provided, all of them must be downloaded from the URL and stored in a directory with a unique
name that will not conflict with any other directories that currently exist or which may be created in
the future
▪ It is the responsibility of the script to handle directory naming and creation, not the users’.
▪ Once all allowed image files have been downloaded from the URL provided (where they exist), the
following information is to be displayed to the terminal in a neat and easy-to-read format:
o A count of how many were downloaded (excluding duplicates, where they exist)
o The directory name into which they were downloaded
o A tabulated summary, with an appropriate header, of all of the image files downloaded
(excluding duplicates, where they exist) and the size of each on disk in bytes, kilobytes or
megabytes as applicable
▪ Your script is also to accommodate an optional -z option (to be used at the command line) that,
when used, will facilitate the adding of all the downloaded image files to a zip archive that is to
reside in the same directory as the downloaded image files and given the same name as this
directory
▪ When the -z option is used, the user is to be informed that the requested zip archive has been
created successfully and where it is located as part of the final summary output
▪ If the user provides an invalid flag, or any other invalid input at all, at the command line, they are to
be informed of this with an appropriate error message and the script terminated with an
appropriate exit code
Here's a Bash script that fulfills the requirements you mentioned:
#!/bin/bash
# Function to print usage message
print_usage() {
echo "Usage: $0 [-z] URL image_type"
echo " -z Create a zip archive of downloaded images"
echo " URL The URL to scan for images"
echo " image_type The image file type (e.g., jpg, jpeg, gif, png)"
exit 1
}
# Check for the -z option
zip_archive=false
if [ "$1" == "-z" ]; then
zip_archive=true
shift
fi
# Check if there are exactly two arguments
if [ $# -ne 2 ]; then
print_usage
fi
# Parse the arguments
url="$1"
image_type="$2"
# Create a directory to store the downloaded images
download_dir="$(date +%Y%m%d%H%M%S)"
mkdir "$download_dir"
# Function to download and check for duplicate images
download_image() {
image_url="$1"
image_name="$(basename "$image_url")"
# Check if the image file type matches the specified type
if [[ "$image_name" == *".$image_type" ]]; then
# Check if the image is already downloaded
if [ ! -e "$download_dir/$image_name" ]; then
echo "Downloading: $image_name"
wget -q -P "$download_dir" "$image_url"
fi
fi
}
# Download images from the provided URL
wget -q -O - "$url" | grep -Eo "(http|https)://[^\"]+" | while read -r line; do
download_image "$line"
done
# Check if any images were downloaded
if [ -z "$(ls -A "$download_dir")" ]; then
echo "No images of type $image_type found at $url."
rmdir "$download_dir"
exit 1
fi
# Create a zip archive if -z option is specified
if [ "$zip_archive" = true ]; then
zip -r "$download_dir.zip" "$download_dir"
echo "Created zip archive: $download_dir.zip"
fi
# Count downloaded images and display summary
num_downloaded_images="$(ls -l "$download_dir" | grep -E '\.'$image_type'$' | wc -l)"
echo "Downloaded $num_downloaded_images images to directory: $download_dir"
echo -e "Summary:\nImage Name\tSize"
ls -lh "$download_dir" | awk '{print $9 "\t" $5}'
# Clean up the downloaded directory
rm -r "$download_dir"
#########################################################
Save this script to a file (e.g., image_downloader.sh), make it executable with chmod +x image_downloader.sh, and then you can run it as follows:
./image_downloader.sh [-z] URL image_type
For example, to download JPEG images from a URL and create a zip archive, you would use:
./image_downloader.sh -z https://example.com jpg
Make sure you have wget and zip installed on your system for this script to work. The script checks for the specified image type and avoids downloading duplicates. It also handles various error cases, as specified in your requirements.
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