Module 7 Review

You have redirected stderr to a file called Errors. You view the contents of this file afterward and notice that there are six error messages. After repeating the procedure, you notice that there are only two error messages in this file. Why?

You did not append the stderr to the Error file, and, as a result, it was overwritten when the command was run a second time.

Which of the following lines can be used to perform command substitution within a shell script? (Choose all that apply.)

`command` d. $(command)

Which command could you use to see a list of all environment and user-defined shell variables as well as their current values?

set

Which of the following files is always executed immediately after any user logs in to a Linux system and receives a BASH shell?

/etc/profile

Which of the following will display the message welcome home if the cd /home/user1 command is successfully executed?

a. cd /home/user1 && echo "welcome home"

Before a user-defined variable can be used by processes that run in subshells, that variable must be __________.

exported

Which of the following operators reverses the meaning of a test statement?

!

Which of the following variables could access the value "/etc" within the sample shell script, if the sample shell script was executed using the bash sample /var /etc /bin command?

$2

Consider the following shell script: echo -e "What is your favorite color?--> \c"read REPLY if ["$REPLY" = "red" -o "$REPLY" = "blue"] then echo "The answer is red or blue." else echo "The answer is not red nor blue." fi What would be displayed if a user executes this shell script and answers Blue when prompted?

The answer is not red nor blue.

A for construct is a loop construct that processes a specified list of objects. As a result, it is executed as long as there are remaining objects to process. True or False?

True

What would be the effect of using the alias command to make an alias for the date command named cat in honor of your favorite pet?

When you use the cat command at the command prompt with the intention of viewing a text file, the date appears instead.

Which construct can be used in a shell script to read stdin and place it in a variable?

read

You attempt to perform the git commit -m "Added listdir function" but the command fails. What are possible reasons for the failure? (Choose all that apply.)

The user performing the commit has not set their Git user information. b. No files were added to the Git index beforehand. c. The user performing the commit is not running the command from within the Git repo directory.

The sed and awk commands are filter commands commonly used to format data within a pipe. True or False?

True

What does &> accomplish when entered on the command line after a command?

It redirects both stderr and stdout to the same location.

The current value for the HOME variable is displayed by which of the following commands? (Choose all that apply.)

echo ~ c. echo $HOME

Every if construct begins with if and must be terminated with? _________

fi

How do you indicate a comment line in a shell script?

Begin the line with #.

Both aliases and functions can be used to store commands that can be executed, but functions can also accept positional parameters. True or False?

True