6.2 Ifs and Lists

Question 1

Explain this if syntax:

if [ ]
then

fi

Answer 1

if -initiates our if statement.

[] - encapsulates the condition.

then - runs following commands if the condition is met.

fi - ends the if statement.

Question 2

Explain this if syntax:

if [ 5 -gt 8 ]
then
echo “This doesn’t make sense!”
fi

Answer 2

if [ 5 -gt 8 ] - This will check to see if 5 is greater than 8.

then - Runs the following commands if the condition is met.

echo - “This doesn’t make sense!” Will have the script print to the screen “That
doesn’t make sense”.

fi - ends the if statement.

Question 3

Explain this Else syntax:

if [ ]
then

else

fi

Answer 3

if [ ] - if this test is true…

then - runs the following code.

else - runs the following code if the condition is false.

fi - ends the if statement.

Question 4

Explain && syntax:

if [ ] &&; [ ]
then

fi

Answer 4

if [ ] - checks if one condition is true.

&& - checks if a second condition is true.

Then - runs the following code if both conditions are met.

fi - ends the if statement.

Question 5

Explain this || syntax:

if [ ] || [ ]
then

else

fi

Answer 5

if [ ] if condition 1 is true.

|| [] or if condition 2 is true.

then run the following code.

else runs code if both conditions are false.

fi ends the if statement.

Question 6

Explain this command:

output=$HOME/research/sys_info.txt

Answer 6

Create a variable to hold the path of your output file. sys_info.txt

Question 7

A __________ is a temporary store for a piece of information. There are two actions we may perform for variables:

1. 2.

Answer 7

A variable is a temporary store for a piece of information. There are two actions we may perform for variables:

1. Setting a value for a variable
2. Reading the value for a variable

Question 8

Explain the following:

if [ ]

then

fi

Answer 8

Runs code if the condition is met.

Question 9

Explain the following:

if [ ]

then

else

fi

Answer 9

Runs code if the condition is met. If condition isn’t met, it will run a different command.

Question 10

Explain the following:

if [ ] && [ ]

then

fi

Answer 10

Runs code if more than one condition is met.

Question 11

Explain the following:

if [ ] || [ ]

then

else

fi

Answer 11

Runs code if only one of multiple conditions are met.

Question 12

Conditionals and Comparisons

=

Answer 12

This item is equal to another

Question 13

Conditionals and Comparisons

==

Answer 13

If two items are equal.

Question 14

Conditionals and Comparisons

!=

Answer 14

If two items are not equal

Question 15

Conditionals and Comparisons

-gt

Answer 15

If one integer is greater than another.

Question 16

Conditionals and Comparisons

-lt

Answer 16

If one integer is less than another.

Question 17

Conditionals and Comparisons

-d /path_to/directory

Answer 17

Checks for existence of a directory.

Question 18

Conditionals and Comparisons

-f /path_to?files

Answer 18

Checks for existence of a file.