[SOLVED] COMP9044 Lab 3

Before the lab you should re-read the relevant lecture slides and their accompanying examples.

Create a new directory for this lab called lab03, change to this directory, and fetch the provided code for this week by running these commands:

$ mkdir lab03

$ cd lab03

$ 2041 fetch lab03

Or, if you’re not working on CSE, you can download the provided code as a zip file or a tar file.

Write a shell script jpg2png.sh which converts all images in JPEG format in the current directory to PNG format.

You can assume that JPEG files and only JPEG files have the suffix jpg.

If the conversion is succesful the JPEG file should be removed.

Your script should stop with the error message shown below and exit status 1 if the PNG file already exists.

When you think your program is working, you can use autotest to run some simple automated tests:

$ 2041 autotest jpg2png

Autotest Results

95% of 447 students who have autotested jpg2png.sh so far, passed all autotest tests.

97% passed test jpg2png_0

96% passed test jpg2png_1

97% passed test jpg2png_2

96% passed test jpg2png_3

When you are finished working on this exercise, you must submit your work by running give:

$ give cs2041 lab03_jpg2png jpg2png.sh

before Tuesday 23 June 17 59 to obtain the marks for this lab exercise.

Write a shell script email_image.sh which given a list of image files as arguments displays them one-by-one. After the user has viewed each image the script should prompt the user for an e-mail address. If the user does enter an email address, the script should prompt the user for a message to accompany the image and then send the image to the specified e-mail address.

$ ./email_image.sh penguins.png treefrog.png

Address to e-mail this image to? [email protected] Message to accompany image? Penguins are cool. penguins.png sent to [email protected]

Address to e-mail this image to? [email protected] Message to accompany image? This is a White-lipped Tree Frog treefrog.png sent to [email protected]

Hints

The program display(1) can be used to view image files

The program mutt(1) can be used to send mail from the command line including attachments, for example:

$ echo ‘Penguins are cool.’|mutt -s ‘penguins!’ -e ‘set copy=no’ -a penguins.png — [email protected]

There is no autotest and no automarking of this question.

When you are finished working on this exercise, demonstrate your work to another student in your lab and ask them to enter a peer assessment. It is preferred you do this during your lab, but if this is not possible you may demonstrate your work to any other COMP(2041|9044) student before Tuesday 23 June 17 59. Note, you must also submit the work with give.

When you are finished working on this exercise, you must submit your work by running give:

$ give cs2041 lab03_email_image email_image.sh

before Tuesday 23 June 17 59 to obtain the marks for this lab exercise.

Write a shell script date_image.sh which, given a list of image files as arguments, changes each file so it has a label added to the image indicating the time it was taken. You can assume the last-modification time of the image file is the time it was taken.

So for example if we run these commands:

$ cp -p /web/cs2041/20T2/activities/date_image/penguins.jpg  .

$ ls -l penguins.jpg

-rw-r–r– 1 andrewt andrewt 58092 Mar 16 16:08 penguins.jpg

$ ./date_image.sh penguins.jpg

$ display  penguins.jpg

There is no autotest and no automarking of this question.

When you are finished working on this exercise, demonstrate your work to another student in your lab and ask them to enter a peer assessment. It is preferred you do this during your lab, but if this is not possible you may demonstrate your work to any other COMP(2041|9044) student before Tuesday 23 June 17 59. Note, you must also submit the work with give.

When you are finished working on this exercise, you must submit your work by running give:

$ give cs2041 lab03_date_image date_image.sh

before Tuesday 23 June 17 59 to obtain the marks for this lab exercise.

Andrew regularly spends time far from the internet and streaming music services such as Spotify, so he has a large collection of MP3 files containing music.

Andrew has a problem: the ID3 tags in the MP3 files in his music collection are incorrect. Unfortunately Andrew’s favourite player software organises music using the information from these ID3 tags. Your task it to fix Andrew’s problem by set the ID3 tags to the correct values. Fortunately the correct value for the tags can be retrieved from the file names and the names of the directories the files are in.

Your task is to write a shell script tag_music.sh, which sets the ID3 tags of MP3 files using the information from file names and directory names.

You’ll first need to make a copy of Andrew’s music collection.

Download music.zip, or copy it to your CSE account using the following command:

$ cp -n /web/cs2041/20T2/activities/tag_music/music.zip .

You assume the names of files and directories follow a standard format. You can determine this format by look at ethe files in Andrew’s music collection.

$ unzip music.zip Archive:  music.zip    creating: music/    creating: music/Triple J Hottest 100, 2007/   inflating: music/Triple J Hottest 100, 2007/2 – Straight Lines – Silverchair.mp3   inflating: music/Triple J Hottest 100, 2007/10 – Don’t Fight It – The Panics.mp3  …

The command id3 can be used to list the value of ID3 tags in an MP3 file. For example:

$ id3 -l ‘music/Triple J Hottest 100, 2013/1 – Riptide – Vance Joy.mp3’ music/Triple J Hottest 100, 2013/1 – Riptide – Vance Joy.mp3:

Title  : Andrew Rocks                    Artist: Andrew

Album  : Best of Andrew                  Year: 2038, Genre: Unknown (255) Comment:                                 Track: 42

But, as you can see, the ID3 tags of this music file have been accidentally over-written. The ID3 tags should be:

$ id3 -l ‘music/Triple J Hottest 100, 2013/1 – Riptide – Vance Joy.mp3’ music/Triple J Hottest 100, 2013/1 – Riptide – Vance Joy.mp3:

Title  : Riptide                         Artist: Vance Joy

Album  : Triple J Hottest 100, 2013      Year: 2013, Genre: Unknown (255) Comment:                                 Track: 1

Fortunately, all the information needed to fix the ID3 tags is available in the name of the file and the name of the directory it is in.

You will write a shell script tag_music.sh which takes the name of 1 or more directories as arguments and fixes the ID3 tags of the all MP3 files in that directory. For example:

Your script should determine Title, Artist, Track, Album, and Year from the directory and filename.

Your script should not change the Genre or Comment fields.

Hints

$ man id3 …

cut almost works for extracting Title and Album from the filename.

Handling the few MP3 files correctly where using _cut doesn’t work will be considered a challenge exercise.

It can be difficult debugging your script on Andrew’s music collection. In cases like these it usually worth creating a smaller data set for initial debugging. Such a tiny data set is available in tiny_music.zip if you want to use it for debugging. This dataset is used in the first autotests.

2020/7/24first autotests.

Download tiny_music.zip, or copy it to your CSE account using the following command:

$ cp -n /web/cs2041/20T2/activities/tag_music/tiny_music.zip .

When you think your program is working, you can use autotest to run some simple automated tests:

$ 2041 autotest tag_music

Autotest Results

72% of 106 students who have autotested tag_music.sh so far, passed all autotest tests.

79% passed test 1993_7

88% passed test 1994

80% passed test 1995_1996

88% passed test 1999

85% passed test 2009_2

74% passed test all

88% passed test tiny_album1 tiny_album2

84% passed test tiny_both

When you are finished working on this exercise, you must submit your work by running give:

$ give cs2041 lab03_tag_music tag_music.sh

before Tuesday 23 June 17 59 to obtain the marks for this lab exercise.

2020/7/24

The test data for the previous question is not really Andrew’s music collection. All the mp3 files contain identical contents. The directories and filenames were created from the source of this web page.

Write a shell script create_music.sh which uses the above webpage to create exactly the same directories and files as in the test data set supplied above.

Your script should take 2 arguments: the name of an MP3 file to use as the contents of the MP3 files you create and the directory in which to create the test data. For example:

When you think your program is working, you can use autotest to run some simple automated tests:

$ 2041 autotest create_music

Autotest Results

62% of 32 students who have autotested create_music.sh so far, passed the autotest test.

When you are finished working on this exercise, you must submit your work by running give:

$ give cs2041 lab03_create_music create_music.sh

before Tuesday 23 June 17 59 to obtain the marks for this lab exercise.

When you are finished each exercises make sure you submit your work by running give.

You can run give multiple times. Only your last submission will be marked.

Don’t submit any exercises you haven’t attempted.

2020/7/24

If you are working at home, you may find it more convenient to upload your work via give‘s web interface.

Remember you have until Tuesday 23 June 17 59 59 to submit your work.

You cannot obtain marks by e-mailing your code to tutors or lecturers.

You check the files you have submitted here.

Automarking will be run by the lecturer several days after the submission deadline, using test cases different to those autotest runs for you. (Hint: do your own testing as well as running autotest.)

After automarking is run by the lecturer you can view your results here. The resulting mark will also be available via give‘s web interface.