Project 4: File System Utilities

Project 4: File System Utilities

Description: In this project, you will write four different programs based on various UNIX
utilities.
You must submit a tar file containing the source code for each utility on separate files, and
a makefile for easy compilation. Because we will be using automated scripts to test your
code, it is important that you follow project structure conventions and that the output
exactly matches the requirements. Before you submit, you should test that your project
behaves as expected when the following commands are typed:
(This is only an example - replace 'Wanwan' with your first name)
$ tar xvf p4-Wanwan.tar
$ ls
makefile myls-Wanwan.c mysearch-Wanwan.c mystat-Wanwan.c mytail-Wanwan.c
$ make
gcc -o myls myls-Wanwan.c gcc -o mysearch
mysearch-Wanwan.c gcc -o mystat mystatWanwan.c gcc -o mytail mytail-Wanwan.c
$ ls
makefile myls myls-Wanwan.c mysearch mysearch-Wanwan.c mystat mystat-Wanwan.c
mytail mytail-Wanwan.c
Stat: Write your own version of the command line program stat, which simply calls the
stat() system call on a given file or directory. Print out file size, number of blocks allocated,
reference (link) count, file permissions, and file inode.
Useful interfaces: stat()
List Files: Write a program that lists files in the given directory. When called without any
arguments, the program should just print the file names. When invoked with the -l flag, the
program should print out information about each file, such as the owner, group,
permissions, and other information obtained from the stat() system call. The program
should take one additional argument, which is the directory to read, e.g., myls -l directory.
If no directory is given, the program should just use the current working directory.
Useful interfaces: stat(), opendir(), readdir(), getcwd().
Tail: Write a program that prints out the last few lines of a file. The program should be
efficient, in that it seeks to near the end of the file, reads in a block of data, and then goes
back until it finds the requested number of lines; at this point, it should print out those lines
from the beginning to the end of the file. To invoke the program, one should type: mytail
-n file, where n is the number of lines at the end of the file to print.
Useful interfaces: stat(), lseek(), open(), read(), close().
Recursive Search: Write a program that prints out the names of each file and directory in
the file system tree, starting at a given point in the tree. For example, when run without
arguments, the program should start with the current working directory and print its
contents, as well as the contents of any sub-directories, etc., until the entire tree, root at the
CWD, is printed. If given a single argument (of a directory name), use that as the root of
the tree instead.
Useful interfaces: you figure it out.
IMPORTANT NOTICE: You are expected to write your own code. Copying from the
Internet is not allowed. All programs will be checked for plagiarism. Submitting code that
is not your own will result in a FF grade on the course.
Grading Rubric: Each utility will be tested using automated scripts and by manual
inspection. Therefore, it is important that all file names match structure described above
(2%), and that you provide a makefile for easy compilation (2%). Each program is worth
24% of the grade, and will be graded according to the following metrics:
[10%] I/O works as expected (e.g., stat prints file size, number of blocks allocated, etc.)
[10%] Correct implementation (e.g., use of APIs such as stat, opendir, lseek, etc)
[ 4%] Programming style (code is organized and well-commented)
Running Example:
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$ ./myls
makefile
myls
mysearch
mystat
mytail
myls-Wanwan.c
mysearch-Wanwan.c
mystat-Wanwan.c
mytail-Wanwan.c
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$ ./mysearch
Current Path /home/w/wanwan/proj4/
Filename: makefile
Filename: myls
Filename: mysearch
Filename: mystat
Filename: mytail
Filename: myls-Wanwan.c
Filename: mysearch-Wanwan.c
Filename: mystat-Wanwan.c
Filename: mytail-Wanwan.c
Search has finished!
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$ ./mystat ./makefile
File Information of ./makefile
File Size: 259 Bytes
Number of Blocks Allocated: 8
Number of Links: 1
File Permissions: -rw-r--r--
File Inode: -198486821
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$ ./mytail 2 ./makefile
These are the last 2 lines of ./makefile:
mytail: mytail-Wanwan.c
 gcc -o mytail mytail-Wanwan.c
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