Graphical user interfaces are super friendly to computer users. They were introduced in reaction to the perceived steep learning curve of command-line interfaces (CLIs).

However, they often require more resources, are less powerful and hard to automate via scripting.

As a computer expert, we want to be more efficient and do our jobs better. We know that command words may not be easily discoverable or mnemonic, so we try to list some common tasks that you might be tempted to do in GUI.

1. copy a file
2. duplicate a file
3. copy a directory
4. duplicate a directory
5. move a file
6. rename a file
7. move a directory
8. rename a directory
9. merge directories
10. create a new file
11. create a new directory
12. show file/directory size
13. show file/directory info
14. open a file with the default program
15. zip a directory
16. unzip a directory
17. peek files in a zip file
18. remove a file
19. remove a directory
20. list directory contents
21. tree view a directory and its subdirectories
22. find a stale file
23. show a calendar
24. find a future date
25. use a calculator
26. force quit a program
27. check server response
28. view content of a file
29. search for a text
30. view an image
31. show disk size
32. check performance of your computer
33. Quick tips
34. Hotkeys
35. I can't remember these cryptic commands

STOP DRAG AND DROPPING A FILE, OR CMD/CTRL + C, CMD/CTRL + V A FILE 👎

Copy readme.txt to the documents directory

$ cp readme.txt documents/

STOP RIGHT CLICKING AND DUPLICATE A FILE 👎

$ cp readme.txt readme.bak.txt

More advanced:

$ cp readme{,.bak}.txt
# Note: learn how the {} works with touch foo{1,2,3}.txt and see what happens.

STOP DRAG AND DROPPING A DIRECTORY, OR CMD/CTRL + C, CMD/CTRL + V A DIRECTORY 👎

Copy myMusic directory to the myMedia directory

$ cp -a myMusic myMedia/
# or
$ cp -a myMusic/ myMedia/myMusic/

STOP RIGHT CLICKING AND DUPLICATE A DIRECTORY 👎

$ cp -a myMusic/ myMedia/
# or if `myMedia` folder doesn't exist
$ cp -a myMusic myMedia/

STOP DRAG AND DROPPING A FILE, OR CMD/CTRL + X, CMD/CTRL + V A FILE 👎

$ mv readme.txt documents/

Always use a trailing slash when moving files, for this reason.

STOP RIGHT CLICKING AND RENAME A FILE 👎

$ mv readme.txt README.md

STOP DRAG AND DROPPING A DIRECTORY, OR CMD/CTRL + X, CMD/CTRL + V A DIRECTORY 👎

$ mv myMedia myMusic/
# or
$ mv myMedia/ myMusic/myMedia

STOP RIGHT CLICKING AND RENAME A DIRECTORY 👎

$ mv myMedia/ myMusic/

STOP DRAG AND DROPPING TO MERGE DIRECTORIES 👎

$ rsync -a /images/ /images2/	# note: may over-write files with the same name, so be careful!

STOP RIGHT CLICKING AND CREATE A NEW FILE 👎

$ touch 'new file'    # updates the file's access and modification timestamp if it already exists
# or
$ > 'new file'        # note: erases the content if it already exists

STOP RIGHT CLICKING AND CREATE A NEW DIRECTORY 👎

$ mkdir 'untitled folder'
# or
$ mkdir -p 'path/may/not/exist/untitled\ folder'

STOP RIGHT CLICKING AND SHOW FILE/directory INFO 👎

$ du -sh node_modules/

STOP RIGHT CLICKING AND SHOW FILE/DIRECTORY INFO 👎

$ stat -x readme.md   # on macOS
$ stat readme.md      # on Linux

STOP DOUBLE CLICKING ON A FILE 👎

$ xdg-open file   # on Linux
$ open file       # on MacOS

STOP RIGHT CLICKING AND COMPRESS DIRECTORY 👎

$ zip -r archive_name.zip folder_to_compress

STOP RIGHT CLICKING AND UNCOMPRESS DIRECTORY 👎

$ unzip archive_name.zip

STOP USING WinRAR 👎

$ zipinfo archive_name.zip
# or
$ unzip -l archive_name.zip

STOP RIGHT CLICKING AND DELETE A FILE PERMANENTLY 👎

$ rm my_useless_file

IMPORTANT: The rm command deletes my_useless_file permanently, which is equivalent to move my_useless_file to Recycle Bin and hit Empty Recycle Bin.

STOP RIGHT CLICKING AND DELETE A DIRECTORY PERMANENTLY 👎

$ rm -r my_useless_folder

STOP OPENING YOUR FINDER OR FILE EXPLORER 👎

$ ls my_folder        # Simple
$ ls -la my_folder    # -l: show in list format. -a: show all files, including hidden. -la combines those options.
$ ls -alrth my_folder # -r: reverse output. -t: sort by time (modified). -h: output human-readable sizes.

STOP OPENING YOUR FINDER OR FILE EXPLORER 👎

$ tree                                                        # on Linux
$ find . -print | sed -e 's;[^/]*/;|____;g;s;____|; |;g'      # on MacOS
# Note: install homebrew (https://brew.sh) to be able to use (some) Linux utilities such as tree.
# brew install tree

STOP USING YOUR FILE EXPLORER TO FIND A FILE 👎

Find all files modified more than 5 days ago

$ find my_folder -mtime +5

STOP LOOKING UP WHAT THIS MONTH LOOKS LIKE BY CALENDAR WIDGETS 👎

Display a text calendar

$ cal

Display selected month and year calendar

$ cal 11 2018

STOP USING WEBAPPS TO CALCULATE FUTURE DATES 👎

What is todays date?

$ date +%m/%d/%Y

What about a week from now?

$ date -d "+7 days"                                           # on Linux
$ date -j -v+7d                                               # on MacOS

STOP USING CALCULATOR WIDGET 👎

$ bc

STOP CTRL + ALT + DELETE and choose the program to kill 👎

$ killall program_name

STOP OPENING A BROWSER 👎

curl -i umair.surge.sh
# curl's -i (--include) option includes HTTP response headers in its output.

STOP DOUBLE CLICKING A FILE 👎

$ cat apps/settings.py
# if the file is too big to fit on one page, you can use a 'pager' (less) which shows you one page at a time.
$ less apps/settings.py

STOP CMD/CTRL + F IN A DIRECTORY 👎

$ grep -i "Query" file.txt

STOP USING PREVIEW 👎

$ imgcat image.png
# Note: requires iTerm2 terminal.

STOP RIGHT CLICKING DISK ICON OR OPENING DISK UTILITY 👎

$ df -h

STOP OPENING YOUR ACTIVITY MONITOR OR TASK MANAGER 👎

$ top

Ctrl + A  Go to the beginning of the line you are currently typing on
Ctrl + E  Go to the end of the line you are currently typing on
Ctrl + L  Clears the Screen, similar to the clear command
Ctrl + U  Clears the line before the cursor position. If you are at the end of the line, clears the entire line.
Ctrl + H  Same as backspace
Ctrl + R  Lets you search through previously used commands
Ctrl + C  Kill whatever you are running
Ctrl + D  Exit the current shell
Ctrl + Z  Puts whatever you are running into a suspended background process. fg restores it.
Ctrl + W  Delete the word before the cursor
Ctrl + K  Clear the line after the cursor
Ctrl + T  Swap the last two characters before the cursor
Esc + T   Swap the last two words before the cursor
Alt + F   Move cursor forward one word on the current line
Alt + B   Move cursor backward one word on the current line
Tab       Auto-complete files and directory names

You can always google or man the commands you are not familiar with. Or, checkout tldr, a collection of simplified and community-driven man pages.