Command Line

Question 1

What is a CLI?

Answer 1

A command-line interpreter or command-line processor uses a command-line interface (CLI) to receive commands from a user in the form of lines of text. This provides a means of setting parameters for the environment, invoking executables and providing information to them as to what actions they are to perform.

Question 2

What is a GUI?

Answer 2

graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, instead of text-based UIs, typed command labels or text navigation. GUIs were introduced in reaction to the perceived steep learning curve of CLIs (command-line interfaces),[3][4][5] which require commands to be typed on a computer keyboard.

Question 3

Give at least one use case for each of the commands listed in this exercise.
- man
- cat
- ls
- pwd
- echo
- touch
- mkdir
- mv
- rm
- cp

Answer 3

• man: man is an interface to the on-line reference manuals. man is the system’s manual pager.
• cat: concatenate files and print on the standard output
• ls: list directory contents. List information about the FILES (the current directory by default).
• pwd: print name of current/working directory. Prints the full filename of the current working directory.
• echo: display a line of text. Echo the STRING(s) to standard output.
• touch: change file timestamps. Update the access and modification times of each FILE to the current time.
• mkdir: make directories. Create the DIRECTORY(ies), if they do not already exist. Mandatory arguments to long options are mandatory for short options too.
• mv: move (rename) files. Rename SOURCE to DEST, or move SOURCE(s) to DIRECTORY.
• rm: remove files or directories. This manual page documents the GNU version of rm. rm removes each specified file. By default, it does not remove directories.
• cp: copy files and directories. Copy SOURCE to DEST, or multiple SOURCE(s) to DIRECTORY.

Mandatory arguments to long options are mandatory for short options too.

• history: GNU History Library. Many programs read input from the user a line at a time. The GNU History library is able to keep track of those lines, associate arbitrary data with each line, and utilize information from previous lines in composing new ones.

Question 4

What are the three virtues of a great programmer?

Answer 4

Laziness, impatience, hubris