But First ...
Intro to Command Line
Slides available at: http://kansascitywomenintechnology.github.io/CommandLine
Last Month
In January we learned about HTML & CSS. We covered:
- HTML & CSS Basics
- Best Practices
- Troubleshooting
What we'll cover
- What is the command line?
- What is the command line used for?
- Common Commands & Practice
But First ...
Inspiring Female Developers
- Katrina Owen@kytrinyx
- Miral Kotb@mkiLuminate
Katrina Owen
Exercism.io
- Katrina accidently became a developer while pursuing a degree in molecular biology.
- She is a backend web developer (ruby)
- Created open source education at exercism.io
- exercism allows you to work in your local dev environment, get feedback from other learners, see how others solved the exercise.
Miral Kotb
iluminate
- Miral combined her passions for dance and computers to create an entertainment experience.
- She studied COmputer Science at Columbia University while studying dance at Barnard College.
- Had a vision of dancers wearing costumes that illuminated wirelessly and complimented the music and coreography
- Showed on America's Got Talent
What is the Command Line?
Text-based interface to interact with your computer
Enter input and return output
- Windows typically uses explorer, finder in mac for a visual interaction
- Different way to interact with computer
- enter commands and computer responds with output
What do I use the command line for?
- Navigate the filesystem
- Run Programs
- Combine Commands
- Automate Common Tasks
- Git
- Scaffolding Projects
- Deployment
- Utilizing Vagrant Environments
- Installing Programs
- Filesystem refers to folders and files on your computer
- What you typically call a folder I'll refer to as a directory
- The filesystem is laid out in heirarchical structure - parent and child directories
- scaffolding - quick set up of app "skeleton"
- Vagrant - quickly set up development environments - type of machine and software - Ask if Jennifer has anything to add about it!!!
- NOTE: Job interviews will ask about CL, most places have command line based build processes.
- Developers often develop tools for other developers to make development easier... sometimes don't have time or skill to create full GUI environments as these are usually time consuming and require different skill set so will create command line based processes so knowing this tool will be helpful
- Npm, bower, webpack, etc
How do I use the Command Line?
Tools:
Navigating the filesystem
Examples:
- pwd - print working directory
- cd - change directory
- ls - list directory contents
Try it!
pwd
ls
cd Documents
HELP! I don't know what I'm doing!
hint: check the online man pages or type "man ls"
- -l displays:
- permissions,
- number of links (number of child directories and files, includes parent and current),
- owner name,
- group name,
- bytes in file,
- date modified,
- file name
- what if you don't know bytes conversions?
- Exit man pages with q, navigate with space for next page, enter for more, arrows
Shortcuts:
- Current Directory:
- Parent Directory:
- Home Directory:
- Root Directory:
- History:
- Previous Command:
- Previous Command:
- Tab completion
- .
- ..
- ~
- /
- history
- !!
- ↑
- home directory contains files for user
- root directory is highest level directory
- handy to know for relative path - these don't include the full path and assume file is on current server (ie. session.html vs http://codingandcocktails.kcwomenintech.org/sessions
File Permissions
- chown - Change file owner
-
chmod - Permissions are set according to numbers.
- 0 = no permissions; cannot read, write, or execute the file
- 1 = execute only
- 2 = write only
- 3 = write and execute (1+2)
- 4 = read only
- 5 = read and execute (4+1)
- 6 = read and write (4+2)
- 7 = read and write and execute (4+2+1)
More Commands
Create a new directory
Try it!
cd ~
mkdir CodingAndCocktails
ls
make sure we have windows explorer or mac finder open!!!
Create a new file
Try it!
cd CodingAndCocktails
touch myNewFile.txt
ls
Write content to a file
Try it!
- echo "Old Fashioned
- Martini
- Mai Tai
- Whiskey Sour
- Cosmopolitan
- Margarita" > myCocktailList.txt
Copy a file
cp sourceFile destinationFile
Try it!
cp myCocktailList.txt newCocktails.txt
ls
Rename or move a file
mv /path/to/sourceFile /path/to/destinationFile
Try renaming!
mv newCocktails.txt renameCocktails.txt
ls
Remove a file
Try it!
rm renameCocktails.txt
ls
View a file
cat to view entire file
tail -n to view the last n lines
head -n to view the first n lines
Try it!
cat myCocktailList.txt
tail -2 myCocktailList.txt
head -2 myCocktailList.txt
Search for a text string
grep - global regular expression print
Try it!
grep Mar myCocktailList.txt
Search for files
find
Try it!
find . –name "*.txt" –mtime 5
Input and Output
- Stdin:
- Stdout (redirect):
- Stdout (append):
- Stderr
- Pipe:
- <
- >
- >>
- |
- Stdin: data going IN to a program (typically coming from keyboard)
- Stdout (file descriptor/indicator to access file: 1): data coming OUT of a program (typically terminal that started program)
- Stderr (2): error data coming OUT of a program (normal to be put in same as stdout 2>&1)
Try it!
grep Mar myCocktailList.txt | wc -w
echo "Bloody Mary" >> myCocktailList.txt
cat myCocktailList.txt
Additional Topics
Editing files in the command line
- vi
- vim
- nano
- emacs
Running Scheduled Tasks with Cron Jobs
added by editing the cron file
specify the schedule you want to run on and the script or command you want to run
* * * * * command to be executed | | | | |_ day of week (0 - 6, 0 = Sunday) | | | |___ month (1 - 12) | | |_____ day of month (1 - 31) | |_______ hour (0 - 23) |_________ minute (0 - 59)
Review
- What is the command line?
- What the command line is used for
- Command line tools
- Filesystem navigation
- Useful commands
- Input & Output
Questions?
?