FIT2100 Assignment Part A:
Building a File Utility
with C Programming
Semester 2 2021
Dr Tawfiq Islam
Lecturer, Faculty of IT
Email: tawfiq.islam@monash.edu
? 2021, Monash University
August 7, 2021
Revision Status
version 2: July 2021 by Tawfiq Islam
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CONTENTS 2
Contents
1 Introduction 3
2 Caveats 3
3 If you require extra help 4
3.1 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4 Task 1: File content viewing functionality with hard-coded options 4
5 Support Command-line Arguments 5
5.1 Task 2: Functionality to support the use of a different source file . . . . . . . 5
5.2 Task 3: Copy file functionality . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5.3 Task 4: Custom View/Copy file functionality . . . . . . . . . . . . . . . . . . 6
5.4 Task 5: Tail View/Copy file functionality . . . . . . . . . . . . . . . . . . . . 6
5.5 Command-line argument summary . . . . . . . . . . . . . . . . . . . . . . . . 7
5.6 Example commands: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
5.7 Important: commenting is required . . . . . . . . . . . . . . . . . . . . . . . 8
5.8 Hints and tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5.9 Marking criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6 Submission 10
6.1 Deliverables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
6.2 Academic Integrity: Plagiarism and Collusion . . . . . . . . . . . . . . . . . . 11
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1 Introduction 3
1 Introduction
In this assignment, you will build a multipurpose file utility1, which combines the simplified
features of multiple Linux utilities such as head, tail, cat, and cp.
This document constitutes the requirement specification for this assignment. You will be
assessed on your ability to both comprehend and comply with the requirements as specified
herein.
Submission due date: 27th August 2021 (Friday) 5:00pm AEST.
Late submissions: A late submission penalty of 10% of the total available marks per day
will apply.
This assignment is worth 15% of the total marks for this unit.
2 Caveats
To complete these tasks, you are allowed to use any of the standard C library functions found
on your virtual machine environment2, except the following:
You are NOT allowed to use any functions available in . This means you cannot
use printf() to produce output. (For example: to print output in the terminal, you will need
to write to standard output directly, using appropriate file system calls.) In addition, you are
NOT allowed to use the system() library function, and any library functions which spawns
new process(s) from your program. This makes the assignment more challenging, but also
means you are interacting with services of the operating system directly.
Your main C source file should be named with your student ID as: 123456789_fileutil.c,
where 123456789 is your student ID.3
1An utility is a software that adds functionality to a computer, or helps users achieve certain tasks.
2For example, you might choose to use getopt or other advanced libraries according to your preference,
but use of any particular library is neither expected nor required, except as required to make system calls.
3If your completed program contains multiple source files, you may name other source and header files as
you wish.
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3 If you require extra help 4
3 If you require extra help
This assignment is an independent learning and assessment exercise.
You may utilise the Ed Discussion Forum to ask questions and obtain clarification, however you
may not share details or code in your implementation with other students, nor may you show
your code to the teaching team prior to submission. This is an assessment task: tutors and
lecturers are not permitted to help you debug your assignment code directly (you are expected
to debug and test your own code), but can help with more general queries, such as queries
related to C programming syntax, concepts and debugging tips.
You may make use of online references with appropriate citation in accordance with academic
integrity policies, however your work must be your own.
3.1 References
The following resources are available on the FIT2100 Unit Information page.
? Curry, David, UNIX Systems Programming for SVR4, Chapter 3: ‘Low-Level I/O Rou-
tines’.
? Curry, David, Using C on the UNIX System, Chapter 3: ‘Low-Level I/O’.
? He, Jialong, LINUX System Call Quick Reference.
4 Task 1: File content viewing functionality with hard-
coded options
Write an utility called fileutil (‘File Utility’) which does the following:
1. Opens a file named sample.txt in the current working directory.
2. Outputs the first 10 lines of the file contents. If the file contains less than 10 lines, then
show entire file contents (to standard output—usually the terminal). Note that, when
the program completes normally, no other output should be produced.
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5 Support Command-line Arguments 5
Your program should always exit ’cleanly.’ This means closing any open files and freeing any
other resources you may have allocated before termination.
If there is a problem accessing the file (e.g. file does not exist), your program should display
an appropriate and sensible error message (you should output this to the program’s standard
error stream rather than standard output) and exit cleanly with a return value of 1. On
successful completion, your program should return an error code of 0.
Write up an instruction manual (user documentation) in a plain text file, explaining how to
compile your program and how to use it. You may use your user documentation itself or any
other text file to test your program.
5 Support Command-line Arguments
Now, extend the functionalities of the same program (from Task 1) to allow the user to run it
with command-line arguments as follows. Extend your user documentation to include all the
added usage functionalities.
5.1 Task 2: Functionality to support the use of a different source
file
Allow the user to specify a different sourcefile as a source (instead of sample.txt) by
putting the filename as a command-line argument. You can assume that the user will provide
the absolute path4 for the file. Note that, if the sourcefile argument is specified, it must
be the first argument. If the sourcefile argument is not specified, the sample.txt should
be used as the source file by default.
5.2 Task 3: Copy file functionality
Instead of showing the contents of the file, allow the user to specify a -d argument at the
command line in order to specify a destination directory where a copy of the source file will
be created, but with only the first 10 lines. If the source file contains less than 10 lines, then
the entire contents of the source file should be copied. When the -d argument is used, the
argument immediately following it should be given as the absolute path of the destination
directory. If it is not, the program arguments are invalid (see Section 5.6).
4An absolute path is defined as a full path beginning with /
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5.3 Task 4: Custom View/Copy file functionality 6
If the destination directory already has a file with the same name as the source file or if the
destination directory does not exist, your program should output an appropriate error message
to standard error then exit cleanly with an error code of 2.
Upon successful completion of the program with this argument, there will be 2 versions of
the same file (i.e. the original file in the source directory with all the file contents, and the
newly created file in the destination directory that contains only the first 10 lines of the original
file). Also, you should output the message "Copy successful" to standard output.
5.3 Task 4: Custom View/Copy file functionality
Instead of copying only the first 10 lines of the file, allow the user to specify a -n argument
at the command line in order to specify how many lines from the source file should be dis-
played/copied. When the -n argument is used, the argument immediately following it should
be given as the number of lines on which an operation should be performed. If it is not, the
program arguments are invalid (see Section 5.6).
Note that, when the -n argument is provided along with the -d argument, the file copy
functionality should be performed. If the -n argument is provided without the -d argument,
the file content viewing functionality should be performed. If the file contains less than n lines,
then display/copy the entire contents of the file.
In case of the copy functionality, if the destination directory already has a file with the same
name as the source file or if the destination directory does not exist, your program should
output an appropriate error message to standard error, then exit cleanly with an error code
of 2. If the copy functionality was performed, you should also output the message "Copy
successful" to standard output.
5.4 Task 5: Tail View/Copy file functionality
Allow the user to specify a -L argument at the command line to indicate that the last 10 lines
of the file should be displayed/copied. As before, the appropriate success or error messages
should be outputted, and the entire file contents should be displayed/copied if the file contains
less than 10 lines.
Note that, when the -L argument is provided along with the -d argument, the file copy
functionality should be performed. If the -L argument is provided without the -d argument,
the file content viewing functionality should be performed. If the -n argument is also present
along with the -L argument, the desired operation should be performed on the last n lines.
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5.5 Command-line argument summary 7
5.5 Command-line argument summary
A summary of all the command-line arguments and their functionalities are shown in the table
below:
Table 1: Summary of functionalities for different command-line arguments.
Command-line
Argument Functionality
sourcefile
Allows the user to input a path for the sourcefile to display/copy.
sourcefile must appear immediately after the command (e.g., ./fileutil sourcefile).
-d destdir Allows the user to input a path for the destination directory for copying the source file.(destdir must appear immediately after -d)
-n numlines Allows the user to input a number to specify how many lines of text should be displayed/copied.(numlines must appear immediately after -n)
-L Makes the program to switch to Tail mode where the View/Copy should be performed on the
last 10 (or n) lines.
Some command-line arguments have dependencies on other arguments (as mentioned above).
The position of the sourcefile argument is fixed. If it appears, it must be the first
argument. However, the ordering of the rest of the arguments is NOT fixed and can vary. For
example, check the last 2 example commands in Section 5.6.
Do not collect these options from standard input, or prompt the user to enter them.
They should be specified as program arguments.
5.6 Example commands:
? $ ./fileutil
Displays the first 10 lines of the sample.txt file from the current directory
? $ ./fileutil -n 20
Displays the first 20 lines of the sample.txt file from the current directory
? $ ./fileutil /home/student/dir1/a.txt
Displays the first 10 lines of the a.txt file
? $ ./fileutil /home/student/dir1/a.txt -n 20
Displays the first 20 lines of the a.txt file
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5.7 Important: commenting is required 8
? $ ./fileutil /home/student/dir1/a.txt -d /home/student/dir2/
Copy a.txt to dir2 where the newly created a.txt only contains the first 10 lines
? $ ./fileutil /home/student/dir1/a.txt -d /home/student/dir2/ -n 15
Copy a.txt to dir2 where the newly created a.txt only contains the first 15 lines
? $ ./fileutil /home/student/dir1/a.txt -d /home/student/dir2 -n 15 -L
Copy a.txt to dir2 where the newly created a.txt only contains the last 15 lines
? $ ./fileutil -d /home/student/dir2
Copy the first 10 lines of sample.txt from the current directory to dir2
? $ ./fileutil /home/student/dir1/a.txt -n
Invalid argument, no line numbers specified after the -n argument!
? $ ./fileutil /home/student/dir1/a.txt -d -L /home/student/dir2
Invalid argument: immediately after -d, a directory path was expected
? $ ./fileutil /home/student/dir1/a.txt -d /home/student/dir2 -L
Copy a.txt to dir2 where the newly created a.txt only contains the last 10 lines
? $ ./fileutil /home/student/dir1/a.txt -L -n 15 -d /home/student/dir2/
Copy a.txt to dir2 where the newly created a.txt only contains the last 15 lines
? $ ./fileutil /home/student/dir1/a.txt -d /home/student/dir2/ -n 15 -L
Copy a.txt to dir2 where the newly created a.txt only contains the last 15 lines
5.7 Important: commenting is required
Commenting your code is essential as part of the assessment criteria (refer to Section 5.9).
All program code should include three types of comments:
(a) File header comments at the beginning of your program file, which specify your name,
your Student ID, the start date and the last modified date of the program, as well as
with a high-level description of the program.
(b) Function header comments at the beginning of each function should describe the func-
tion, arguments and interpretation of return value.
(c) In-line comments within the program are also part of the required documentation.
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5.8 Hints and tips 9
5.8 Hints and tips
Do... Don’t... (!)
+ read up on low-level I/O system calls – use fancy C library functions that
don’t demonstrate your understanding of mak-
ing system calls to the OS directly.
+ write normal program output to standard
output
– write error messages to standard output (use
standard error instead)
+ close open files before exiting and free any
manually-allocated memory
– terminate without cleaning up first
+ check return values and handle error condi-
tions
– act in undefined ways when a parameter is
invalid or a file can’t be opened
+ access and modify valid memory – attempt to set values in undefined pointers
+ read up on argc and argv – prompt the user to enter options after your
program has started
+ write user documentation in a plain text file – submit user documentation in a Word docu-
ment or PDF
+ in user documentation: explain all function-
ality to those who might use your program
– expect your users to understand the C code
inside your program (users are not always pro-
grammers!)
+ use descriptive, self-explanatory variable
names
– use vague single-character variable names
+ break your program logic into multiple func-
tions
– stuff everything into a single main function
+ use consistent code indentation for clarity – use inconsistent indentation or fail to indent
nested code blocks
+ comment your code with file header, function
header and inline comments
– write uncommented code or add comments
at the last minute
+ test your program in the specified VM envi-
ronment
– forget to run your finished program through
valgrind to test for memory access bugs
+ use the Ed Discussion Forum – implement each task as a separate pro-
gram
+ read the assignment specification care-
fully and thoroughly
– treat this table as a substitute for read-
ing the spec carefully.
5.9 Marking criteria
Each task is worth an equal share of the total. The same marking criteria will be applied on
all tasks:
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6 Submission 10
? 50% for working functionality according to specification.
? 20% for code architecture (algorithms, use of functions for clarity, appropriate use of
libraries, correct use of pointers, etc. in your implementations of all the tasks.)
? 10% for general coding style (clarity in variable names, function names, blocks of code
clearly indented, etc.)
? 20% for documentation (user documentation describes functionality for the relevant task,
code is well-commented.)
6 Submission
There will be NO hard copy submission required for this assignment. You are required to submit
all your deliverables (see Section 6.1) as individual files. Do ensure that your submission
complies with the requirements set out in this specifications document.
Your submission will be done via the assignment submission link on the FIT2100 Moodle site,
and should be submitted by the deadline specified in Section 1, i.e. 27th August 2021
(Friday) 5:00pm AEST.
Note: You must ensure you complete the entire Moodle submission process (do not sim-
ply leave your assignment in draft status) to signify your acceptance of academic integrity
requirements.
Additionally, your program must be able to run in the Linux Virtual Machine environment
which has been provided for this unit. Any implementation that does not run at all in this
environment will receive no marks.
6.1 Deliverables
Your submission should include the following files:
? All C source files (.c format) required to compile and run your program.
? A user documentation file (.txt format) of not more than 80 lines which provides clear
and complete instructions on how to compile your program, and and how to run all of
the requested features.
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6.2 Academic Integrity: Plagiarism and Collusion 11
Your submission may optionally include the following files, if you require them for your
implementation:
? C header files (.h format)
? A makefile
Do not submit compiled executable programs. Marks will be deducted for any of these re-
quirements that are not strictly complied with.
6.2 Academic Integrity: Plagiarism and Collusion
Plagiarism Plagiarism means to take and use another person’s ideas and or manner of express-
ing them and to pass them off as your own by failing to give appropriate acknowledgement.
This includes materials sourced from the Internet, staff, other students, and from published
and unpublished works.
Collusion Collusion means unauthorised collaboration on assessable work (written, oral, or
practical) with other people. This occurs when you present group work as your own or as
the work of another person. Collusion may be with another Monash student or with people
or students external to the University. This applies to work assessed by Monash or another
university.
It is your responsibility to make yourself familiar with the University’s policies
and procedures in the event of suspected breaches of academic integrity. (Note:
Students will be asked to attend an interview should such a situation is detected.)
The University’s policies are available at: http://www.monash.edu/students/academic/
policies/academic-integrity
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