Midterm Questions

Question 1

What would you type at the command line if you wanted to see the value of the variable SHELL?

Answer 1

echo $SHELL

Question 2

What would you type at the command line if you wanted to see the last 10 lines of the file log.txt?

Answer 2

tail log.txt

Question 3

What is the name of the directory at the top of the Unix filesystem?

Answer 3

root

Question 4

What symbol is used to represent the top of the Unix filesystem?

Answer 4

/

Question 5

What is the parent directory?

Answer 5

the directory directly above your current directory

Question 6

Can you have two files with the same name in the same directory?

Answer 6

no

Question 7

What directory are you in when you first log in to a Unix machine?

Answer 7

your own home directory

Question 8

What does the .. (dot dot) in your current directory mean?

Answer 8

the parent directory of your current directory

Question 9

What directory is the starting point for an absolute path?

Answer 9

the root directory

Question 10

What directory is the starting point for a relative path?

Answer 10

the current directory

Question 11

By default, which account is the owner of a file or directory?

Answer 11

the account that created it

Question 12

Name the three types of access permissions.

Answer 12

read, write and execute

Question 13

Name the three categories of accounts which are used in assigning access permissions.

Answer 13

owner, group, everyone else

Question 14

What does the PATH shell variable contain?

Answer 14

the list of directories the shell must search to find the file to run a command

Question 15

If you wanted the program do_something to take input from the file data.txt what would you write at the command line?

Answer 15

do_something < data.txt

Question 16

Look at the diagram on the last page. Assuming that you are in the directory named it, write the absolute pathname you would use to reference the directory named hw inside the it117 directory. You do not have to write a Unix command, I only want the pathname.

Answer 16

/courses/it/it117/hw

Question 17

Look at the diagram on the last page. Assuming that you are in the directory named it, write the relative pathname you would use to reference the directory named hw1 under the it244 directory. You do not have to write a Unix command, I only want the pathname.

Answer 17

it244/hw/hw1

Question 18

Look at the diagram on the last page. Assuming that you are in the directory named it, write the relative pathname you would use to reference the root directory. You do not have to write a Unix command, I only want the pathname.

Answer 18

../..

Question 19

Look at the diagram on the last page. z Assuming that you are in the directory named it, write the relative pathname you would use to reference the bill directory. You do not have to write a Unix command, I only want the pathname.

Answer 19

../../home/bill

Question 20

Look at the diagram on the last page. Assuming that you are in the directory bill, write the command to create a soft link to the hw2 directory. You may use either an absolute or relative pathname.

Answer 20

ln -s /courses/it/hw/hw2

Question 21

Write the single command you would use to change the permissions on the file memo.txt so that the owner could read and write it, the group could only read it and all other users had no permissions whatsoever.

Answer 21

chmod 640 memo.txt

Question 22

Write the single command you would use to change the permissions on the file backup so the owner had all permissions, the group could read and execute the file and all other users cold only execute the file.

Answer 22

chmod 751 backup

Question 23

Write the single command you would use to change the permissions on the directory work so that the owner could do anything, the group could run ls and cd on the directory and all other users could only run ls on the directory.

Answer 23

chmod 754 work

Question 24

Write a single command to create a copy of the file memo.txt in the parent directory into the current directory.

Answer 24

cp ../memo.txt .

Question 25

Using a pipe, write the command line to find all Red Sox games from the file redsox.txt where the Sox lost to a team that was not the Orioles. Entries in the file look like this

2011-07-02 Red Sox @ Astros Win 7-5

2011-07-03 Red Sox @ Astros Win 2-1

2011-07-04 Red Sox vs Blue Jays Loss 7-9

2011-07-05 Red Sox vs Blue Jays Win 3-2

…

Answer 25

grep Loss redsox.txt | grep -v Orioles