¶ CH 0: Programming Environments
Lesson Notes
What are the essential tools for writing code:
- Computer
- A Programming Language
- Storage
¶ Computers are programmable machines
Computers are very dumb. They can only do exactly what you tell them.
Firehose overview of computer terms:
- Operating System: Manages communication between memory, cpu, applications, and devices
- Shell/Command Line/Terminal: Text based version of the Operationg System, a.k.a Terminal, Command Line
- Executable: Any file that contains a set of instructions, i.e. an algorithm, for the CPU
- Input: Data sent to the CPU for processing
- Output: The data result of processing from the CPU
¶ Directory Structure
Although you can code wherever you want, we will be focusing on a Linux environment for this course.
- Directories on a computer are organized as a tree
- The top directory that holds all your files is called
rootand is represented with/
- The top directory that holds all your files is called
Windows directory structure is slightly different from Mac and Linux
¶ CLI
There are hundreds of different commands you can use on the command line. The commands below are the ones you will use most often when first starting out.
pwd- current directory you are inls- list of files in current directorymkdir- creates a new directory in your current working directorycd- change working directory to a new directoryrm- delete a file or foldertouch- create a file or update modified date if the file already existspython3- start the python interpreter to run commands
Many operations are relative to your current directory, such as cd, ls, and python3
- Some commands take parameters
cd myfolder - Some don't
ls
Commands always have the same structure:
<command name> <options> <parameters>
Example:
rm -i myfile.txt
rm: delete file command-i: prompt befopre deletingmyfile.txt: the file to be deleted
It can initially be difficult to remember all the commands. You can always double check how to use commands with the local manual page:
man pwd
Type: man command to get a description of any command
¶ Why use terminal?
Using shell/cli/terminal/command:
- is much faster than point and click once you get used to it
- Allows you to interact with the OS in a way you can’t with the mouse
- Allows you to ‘script’ or automate tasks