Schedule
Labs
Assignments
TA office hours
Topic videos
Some course notes
Extra problems
Lecture recordings
There are five questions and they are equally weighted.
Time allotted: 45 minutes.
Since time is short, be careful not to get stuck on one question to the exclusion of others. Not everyone will necessarily be able to finish this test within the 45 minutes. The amount of marks or answer-space allotted does not indicate how long it will take you to complete the question, nor does the size of the answer-space indicate the size of the correct answer.
Answer all questions. Answer questions in the space provided.
Do not open this booklet until you are instructed to.
1.
Describe in English what patterns of file names in the current directory the following "glob" expressions match. Ignore the issue of file names beginning with a dot. The answer for part 'a' is supplied as an example.
a) *x
b) *x*y*
c) x*x*x
d) *.x
e) *.*
2.
Write a 'while' loop in sh to output the numbers from 1 to 10, by starting with '1' and adding one to it each time around the loop to get the next number. (E.g. don't use seq.)
3.
A shell script containing the following code is executed:
if x then y else z fi
a) Write the command 'x' (either as a shell script, or in C if you prefer) so that the command 'y' will be executed.
b) Write the command 'x' (either as a shell script, or in C if you prefer) so that the command 'z' will be executed.
4.
"for i in *" can be used to loop over all file names in the current directory.
Use this to write shell commands which check whether each file in the current directory contains the string 'good' in the opinion of grep.
For each file containing 'good', output a line of the form
file is good... file is *very* good.
where "file" is the file name.
5.
Here is a portion of a unix filesystem. Like the "ls -l" output, we list whether the file (inode) is a plain file, directory, etc, with '-' for plain file or 'd' for directory. In the case of directories, the table also states the data content of the directory itself (a list of pairs of name and inode number).
| 2 | d | . 2, .. 2, usr 8, etc 4, bin 7 |
| 3 | - | |
| 4 | d | . 4, .. 2, passwd 3 |
| 5 | - | |
| 6 | d | . 6, .. 8, fsys.fig 5, src 21 |
| 7 | d | . 7, .. 2, date 18 |
| 8 | d | . 8, .. 2, bin 9, ajr 6, you 22 |
| 9 | d | . 9, .. 8 |
| 10 | ||
| 11 | ||
| 12 |
a) Suppose I do "mkdir /usr/ajr/newdir". Write in all changes/additions to the above list. (There are some free inodes at the end for you to use for new files.)
b) Suppose that my current directory is /usr/ajr and I do "ln fsys.fig more.fig". Write in all changes/additions to the above list.