Command Line Interface/General Info (I)

Question 1

What are two ways to control/command a computer?

Answer 1

1-GUI (mouse/click/tap/icons)

2-the Command Line Interface

Question 2

What is the main purpose of the command line?

Answer 2

To manipulate a computer’s files, directories and programs (move, rename, execute, copy, etc.)

Question 3

What is the most common OS for servers?

Answer 3

Linux (Mac OS and Unix are similar to it)

Question 4

What are the prompt icons for the Bash shell and the Zsh shell?

Answer 4

Bash = $

Zsh = %

Question 5

When you are logged in as the admin user (“root”), what is the prompt icon?

This same icon is also used for what?

Answer 5

#

Comments

Question 6

What is the main reason to learn how to use the command line?

Answer 6

To do system admin tasks such as installing software, compiling/running code, debugging server issues, managing system logs, and restarting servers

Question 7

What is “rubber duck debugging?”

Answer 7

When you have coding errors, it is the technique of explaining your code aloud line-by-line to a rubber duck, with the idea that doing so will allow you to hopefully come across a solution.

Question 8

An interface allows you to control a computer. What are the two main parts of an interface?

Answer 8

1-a display of info about what the computer is doing

2-a way to tell the computer what to do

Question 9

Here is a prompt:

scottjones@Scotts-Air ~ %

Identify each part of the prompt:

scottjones.  =  ?
Scotts-Air   = ?
~  = ?

Answer 9

scottjones = the user/the person who is logged into the command line interface

Scotts-Air = the host/the name of the computer

~ = this space shows your current directory (in this example, it’s the home directory)

Question 10

What are the four items that make up the CLI display?

1-the p______
2-the c______
3-the i______
4-the o_______

Answer 10

1-the prompt
2-the cursor
3-the input
4-the output

Question 11

True or false?

A command can be a path to a file.

Answer 11

True

Question 12

What are arguments/strings?

Answer 12

Pieces of info passed to a command.

Question 13

Are arguments always need for a commands?

Answer 13

No.

Question 14

What is a flag? Where are they placed after a command?

Answer 14

A special type of argument. They are usually placed before the other arguments.

Question 15

What do flags look like? (there are two types)

Answer 15

abbreviated flags/one dash:
-s, -z, c, etc.
(These can be combined: -c, -s, -z = -csz )

full-word flags/two dashes:
- -format, etc.

Question 16

In the command line, what is the only context to tell you where are?

Answer 16

the file system

Question 17

True or false?

In the file system, directories are files.

Answer 17

True

There is the phrase “non-directory files” to distinguish the files inside a directory

Question 18

What do the following symbols mean?

/

. ( or ./ )

.. ( or ../ )

../.. ( or ../../ )

~

*

Answer 18

/ = the root directory OR a directory separator

. = current directory/same level

.. = navigate up a level to the parent directory

../.. = navigate up two levels to the grandparent directory

~ = the home directory

• = “splat operator”/it represents any characters you give it. For example, find all files ending in “or”, etc.

Question 19

What is the difference between these:

/home/job

home/job

Answer 19

• this path starts at the root directory, and ends at “job,” which is a file or sub-directory inside of the directory “home”
• “home” is your current directory, and “job” is a file or sub-directory inside “home”

Question 20

What is an executable?

Answer 20

A special type of file that can be used as a command

Examples: echo, touch

Question 21

True or false?

A command is a file.

Answer 21

True

Question 22

True or false?

All files are commands.

Answer 22

False

Question 23

Do all executables require you to type out their paths?

Answer 23

No. The common/installed ones don’t require it. Some common ones are “touch” and “echo.” You could add the paths if you wanted to, but it’s not necessary b/c the command line knows where to look to find them

YOU COULD TYPE:
echo “hello”
OR:
/bin/echo “hello”

Question 24

What character do hidden files start with?

Answer 24

.

hidden files are also called “dot files”

.bashrc
.cache
etc.

Question 25

What does this mean?

jobs/

Answer 25

“jobs” is your current directory