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CS 140U
50 POINTS
DUE announced in class
NAME:
INSTRUCTIONS:
a) Login to your UNIX account and make sure C-Shell is
your current shell.
b) Do the steps is each question and write the required answer in the
space provided.
c) For questions 12-16 assume a file named students containing the
following data exists in your current directory. Each line in this file represents a
student's first name, last name, and 3 exam scores. Each line should be regarded as a
record containing 5 fields separated by one or more tab characters. You must use the awk
command to answer these questions (Note: This file exists in
/u/staff/si/CS140U/PUBLIC/hw5.dat).
Tom Jones
100 90 80
Nancy Jones 70 80
90
Terry Sims 55 65
75
John Terry 75 76
77
Ruth Maier 100 100
100
Mike Wolfe 90 95
98
Dennis Cole 70 80
89
Ron Maier 90 85
89
Susan Miller 65 80
90
Mad Bill 75 65
77
1) What is the output for each of the following
echo commands?
% set n = "Ken Thompson"
a) % echo n
b) % echo $n
c) % echo "$n"
d) % echo 'n'
e) % echo \$n
2) Using the variable n in the previous question
and the echo command, write a command line that displays the following message:
"The value in variable n is $n and is equal to ken Thompson"
Note: This should work for any variable named n (with any contents).
The double quotes must be displayed as well.
3) There are two special characters that can't be turned off with
either single or double quotations (in C-shell). What are these characters?
4) Explain the difference between the .cshrc and the .login files in a
user's home directory (Note: in terms of how when they are processed by the C-shell).
5) How are the following commands different?
a) % set d = date
b) % set d = `date`
6) First view the contents of the /etc/passwd file a few times to get
familiar with its contents. Then, using the grep command, display the entry for your
account in the /etc/passwd file (can assume that your user information has been updated
with the chfn command). Note: for this question just write the command line for the grep
command.
7) Using the grep command display a list of currently logged in users
whose account name begins with the same letter as your account (use the output of who and
pipe). Note: Just write the command line that accomplishes this.
8) Using the grep command display a long list of all directories (only)
in your ~. Note: just write the command line.
9) Use the grep command to display your ~/.cshrc file with line
numbers. Note: just write the command line.
10) How are the following file (or directory) references different in
C-shell?
a) ~xyz
b) ~/xyz
11) Using the grep command create an alias that displays the number of
login sessions a particular user (any user) is currently using.
12) What command line would display the contents of the students file
with line numbers in front of each line?
13) What command line would display the contents of students file such
that first names and last names are swapped?
14) What command line would display the contents of the students file
with the following logo?
FIRST_NAME LAST_NAME
EXAM1 EXAM2 EXAM3
15) What command line would only display the number of
lines in the students file?
16) What command line would display the first and last names of those
who got 100 on their first exam (there are examples in the book)?
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