COMP9044 Week 10 Laboratory Exercises Solution

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


Create a new directory for this lab called lab10, change to this directory, and fetch the provided code for this week by running these commands:
$ mkdir lab10
$ cd lab10
$ 2041 fetch lab10
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 program, which_webserver.sh which given the URL of 1 or more webservers as command-line arguments prints what software the webserver is running, as indicated by the server field returned in a request to the web server.
Match the output and behaviour in the example below exactly:
$ ./which_webserver.sh https://www.unsw.edu.au https://www.unsw.edu.au Apache/2.4.34 (Red Hat) OpenSSL/1.0.1e-fips PHP/5.6.25
$ ./which_webserver.sh https://www.google.com https://www.google.com gws
$ ./which_webserver.sh https://www.netflix.com https://www.netflix.com nq_website_nonmember-prod-release b2b0bc7b-bffd-4024-b8b8-d060e658f2ac $ ./which_webserver.sh https://www.abc.net.au https://www.sydney.edu.au http://www.bom.gov.au https://www.abc.net.au Apache/2.4.43 (Unix) https://www.sydney.edu.au Apache http://www.bom.gov.au Apache
Hint
man curl
Assumptions
Your answer must be Shell. You can not use other languages such as Perl, Python or C.
No error handling is necessary.
When you think your program is working, you can use autotest to run some simple automated tests:
$ 2041 autotest which_webserver
When you are finished working on this exercise, you must submit your work by running give:
$ give cs2041 lab10_which_webserver which_webserver.sh

Write a Shell program, make_tree.sh which is given the pathname of a directory tree.
It should search this directory tree for directories containing a makefile.
For each of these directories it shouldprint the directory pathname and then run make in the directory.
Match the output and behaviour in the examples below exactly:

$ unzip /web/cs2041/20T2/activities/make_tree/examples.zip
$ find simple simple simple/b.c simple/Makefile
$ ./make_tree.sh simple/ Running make in simple clang -Wall -c -o b.o b.c clang -Wall -o p b.o $ find medium medium medium/a medium/a/x.c medium/a/h.c medium/a/Makefile medium/a/l.c medium/b medium/b/b.c medium/b/j.c medium/b/k.c medium/c medium/c/p.c medium/c/Makefile $ ./make_tree.sh medium Running make in medium/a clang -Wall -c -o h.o h.c clang -Wall -c -o l.o l.c clang -Wall -c -o x.o x.c clang -Wall -o c h.o l.o x.o Running make in medium/c clang -Wall -c -o p.o p.c clang -Wall -o d p.o
$ find hard hard hard/a hard/a/p.c hard/a/r.c hard/a/Makefile hard/a/q.c hard/b hard/b/b hard/b/b/b hard/b/b/b/b hard/b/b/b/b/b hard/b/b/b/b/r.c hard/b/b/b/b/Makefile hard/c hard/c/d hard/c/d/o.c hard/c/d/Makefile hard/c/e hard/c/e/a.c hard/c/e/b.c hard/c/e/f hard/c/e/f/a.c hard/c/e/f/Makefile $ ./make_tree.sh hard Running make in hard/a clang -Wall -c -o p.o p.c clang -Wall -c -o r.o r.c clang -Wall -c -o q.o q.c clang -Wall -o b p.o r.o q.o Running make in hard/b/b/b/b clang -Wall -c -o r.o r.c clang -Wall -o r r.o Running make in hard/c/d clang -Wall -c -o o.o o.c clang -Wall -o m o.o Running make in hard/c/e/f clang -Wall -c -o a.o a.c clang -Wall -o i a.o
The test directories are also available as a zip file
If make_tree.sh is give extra command line arguments they should be passed to each make command, for example:
$ cat simple/Makefile
CC=clang CFLAGS=-Wall
p: b.o
$ (CC) $(CFLAGS) -o $@ $^
.PHONY: clean
clean: rm -f b.o
clobber: clean rm -f p
$ ./make_tree.sh medium clobber Running make in medium/a rm -f h.o l.o x.o rm -f c
Running make in medium/c rm -f p.o rm -f d
$ ./make_tree.sh hard clean Running make in hard/a rm -f p.o r.o q.o
Running make in hard/b/b/b/b rm -f r.o
Running make in hard/c/d rm -f o.o
Running make in hard/c/e/f rm -f a.o
Hint
Use find to find all Makefiles in the directory tree.
Assumptions
You can assume makefiles are named Makefile
Your answer must be Shell. You can not use other languages such as Perl, Python or C.
No error handling is necessary.
When you think your program is working, you can use autotest to run some simple automated tests:
$ 2041 autotest make_tree
When you are finished working on this exercise, you must submit your work by running give:
$ give cs2041 lab10_make_tree make_tree.sh


Write a Shell program, compress_if_needed.sh which takes the pathnames of 0 or more files as command line arguments.
It should compresses each file with xz if and only if, this results in a smaller file.
Match the output and behaviour in the example below exactly:
$ unzip /web/cs2041/20T2/activities/compress_if_needed/examples.zip
$ ls -l file*
-rw-r--r-- 1 andrewt andrewt 4096 Aug 3 17:10 file1.bin
-rw-r--r-- 1 andrewt andrewt 4096 Aug 3 17:10 file2.bin
$ ./compress_if_needed.sh file1.bin file2.bin file1.bin 4096 bytes, compresses to 4156 bytes, left uncompressed file2.bin 4096 bytes, compresses to 2160 bytes, compressed
$ ls -l file*
-rw-r--r-- 1 andrewt andrewt 4096 Aug 3 17:10 file1.bin
-rw-r--r-- 1 andrewt andrewt 2160 Aug 3 17:10 file2.bin.xz
The two test files are also available as a zip file
Assumptions
Your answer must be Shell. You can not use other languages such as Perl, Python or C.
You should use xz's default compression. xz has many options to change compression behaviour. Do not use these.
When you think your program is working, you can use autotest to run some simple automated tests:
$ 2041 autotest compress_if_needed
When you are finished working on this exercise, you must submit your work by running give:
$ give cs2041 lab10_compress_if_needed compress_if_needed.sh


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.
You check the files you have submitted here.
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.
Lab Marks
When all components of a lab are automarked you should be able to view the the marks via give's web interface or by running this command on a CSE machine:
$ 2041 classrun -sturec

For all enquiries, please email the class account at cs2041@cse.unsw.edu.au
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