Command Line Flashcards
What is a CLI?
Command line interface
What is a GUI?
graphical user interface
man
to get the manual on a command. Man cat for example.
cat
print the contents of a file or concatenate multiple files.
ls
display a list of contents of a directory.
pwd
print working directory
echo
can use echo to print messages and then create new txt files with that message
echo hello world > hello.txt
touch
touch changes file timestamps. creates new files
mkdir
make directory mkdir parent
mkdir -p parent/child/grandchild
mv
move command, used to rename directorys or move.
mv pokiemans to pokemon
rm
remove command
rm lol.txt
rm -r directoryname to delete all of its contents
cp
copy
cp nameoffile newnameofcopy
history
shows history of all recent command line commands to your terminal.
what are 3 features of a great programmer.
laziness, hubris, impatience
What is Node.js?
Node.js is a program that allows JavaScript to be run outside of a web browser. It is commonly used to build back ends for Web applications, command-line programs, or any kind of automation that developers wish to perform.
What can Node.js be used for?
It is commonly used to build back ends for Web applications, command-line programs, or any kind of automation that developers wish to perform.
What is a REPL?
A read–eval–print loop (REPL), also termed an interactive toplevel or language shell, is a simple interactive computer programming environment that takes single user inputs, executes them, and returns the result to the user;
console or gitbash
When was Node.js created?
may 27 2009 by ryan dhal
What back end languages have you heard of?
Java, ruby, python
What is the process object in a Node.js program?
object that contains meta information, and control over the current node js process.
How do you access the process object in a Node.js program?
just grab it, it always exists
What is the data type of process.argv in Node.js?
its an array of strings
What is a JavaScript module?
in JavaScript, a “module” is a single .js file
What values are passed into a Node.js module’s local scope?
exports, __filname, __dirname, require, module
Give two examples of truly global variables in a Node.js program.
process, console
What is the purpose of module.exports in a Node.js module?
to export a desired item you attach to the exports property of the module.object
How do you import functionality into a Node.js module from another Node.js module?
module.exports = add
const add = require('./add');what is the javascript event loop?
function calls stack on top of the stack. Returns pop off stack.
event loop has to wait for the stack to be clear to push the callback into the stack from the task queue.
What is different between “blocking” and “non-blocking” with respect to how code is executed?
What is a directory?
What is a relative file path?
its a path to a file from where you are
what is an absolute file path?
the root of the file system, just a slash.
What module does Node.js include for manipulating the file system?
the fs module.
What method is available in the Node.js fs module for writing data to a file?
fs.writeFile
Are file operations using the fs module synchronous or asynchronous?
asynchronous and synchronous. fs.writeFileSync try catch if for synchronous code.
What is NPM?
npm is a package manager for the JavaScript programming language maintained by npm. made up of 3 things: website, registry or the cli.
What is a package?
a package is a directory with multiple files or modules and a package.json
How can you create a package.json with npm?
npm init –yes
What is a dependency and how to you add one to a package?
npm install jquery a dependency is third party code library that your application depends on to function.
What happens when you add a dependency to a package with npm?
adds module to node_modules directory and the package.json is updated with the dependency
how to vet a npm package.
visibility, documentation, userbase
