Terminal & Shell

The idea at this point is to make them comfortable with working in the terminal. When programming foundations start, it will pay off.

Base material:

Session 1

• File System
  • Draw on board the tree (root > folder > more folders etc.)
  • They have been creating this through UI (mouse till now)
• Terminal vs Shell
• Commands:
  • pwd
  • ls
  • cd
    • explain:
      • cd .. and cd ~ (~ is home, not root)
  • mkdir
    • when they try to make multiple directories using one command each, show them mkdir d1 d2 d3 (faster than UI, they can start to see the value!)
    • Also, what if "d1 d2" should be file name, need to wrap in quotes.
  • touch
  • cat
  • echo
    • Then combine echo with >:
      • echo "Hello World" > file.txt
      • >> for append
  • cp
  • mv : show both move and rename with this
  • rm
  • rmdir

Practice in between, ask them to create this structure using terminal commands they just learned:

Frappeverse
-------> photos
--------------> mumbai
----------------------> all.txt
-------> blog
-------------> <your-name>.txt

Session 2 <Practice with TAs>

Make them run commands on their computers (by Shivam)

Session 3

• history
• Tab Completions and Up Arrow Key for navigating through history
• grep (the very basics) (take an example where the file contains multiple lines and occurrences of the word)

grep apple fruits.txt

• Command anatomy:
  • e.g. cp hello.txt backup/
  • command argument argument
• Flags
  • e.g. ls -l ls -a (good time to make them see the difference that just ls will not show hidden (i.e. starting with a .) files and folders.
• wc (stands for word count):

wc fruits.txt # 5 14 65 story.txt
wc -l fruits.txt # 5 story.txt

In the above, 5 is the number of lines, 14 is the number words, and 65 is the number of bytes in the given file(s). If -l option is given, only number of lines are printed.

• man (manual pages) and --help
  • show for wc etc.
  • they should be able to at least skim
• Wildcards
  • e.g. list all jpg images in a file, all files starting with the letter p
    • ls *.jpg and ls p*
  • then expand to show how the wildcards are not just in ls but can be used to carry out copy, move etc.
    • move all jpg images to images/ folder etc.
    • e.g. math_1.txt math_2.txt math_3.txt cs_1.txt cs_2.txt cs_3.txt move math notes to math/ folder and cs notes to cs/ folder.

Session 4 <Practice with TAs>

Practice with TAs.

Session 5

• head and tail
  • head / tail by default 10 lines
  • head -n 5 first 5 lines, with tail last 5 lines.
  • show examples
• (important to understand) redirection
  • analogy of redirecting someone from where he was actually "directed" towards
  • it was going to come on screen, but we asked the shell program to redirect it to some file instead
  • Show if "ls >> list.txt", list.txt will get auto created if not exists, don't have to touch.
• (important to understand) pipe
  • Again analogy to actual pipe connecting different chambers (e.g. water treatment plan) where each chamber does some mixing and the contents are forwarded to the next output pipe
  • Take examples and make them practice:

$ ls | grep "apple" # list of files/dir that have apple in their name
$ history | tail -n 50 | grep "mkdir" > commands.txt

Good opportunity to give textual questions and see if they can breakdown the problem and chain the commands to get it done.