A quick introduction to the UNIX command line

####Before we start

You may want to set up a remote development environment (particulary if you are not running OS X or Linux).

Sign up for Nitrous.IO, have a quick read through the Getting Started guide and set up a Python/Django box. You can then login and open up a console window.

Or, if you prefer, just open a terminal window on your computer.

####Additional learning resources

After you have worked through the quick summary below, you can take a look at The Command Line Crash Course.

And to get the commands into your head, have a go at this course on Memrise.

####A quick step-by-step summary of the basics

#####Where am I?

pwd

“Print Working Directory”

#####What’s in my current directory?

ls

“LiSt”

#####Show me hidden files, as well:

ls -a

#####And show me details of each file:

ls -l

#####Show me both details and hidden files:

ls -al

#####Make a new directory called things:

mkdir things

“MaKe DIRectory”

#####Change to the things directory:

cd things

“Change Directory”

#####Go up a directory level:

cd ..

#####Return to my home directory:

cd ~

#####Create a new file with nothing in it:

touch one.txt

touch changes the access and modification time of a file (i.e. it touches it), but this also creates a new file if none exists with the name given.

#####Make a copy of it:

cp one.txt two.txt:

“CoPy”

#####Change its name:

mv one.txt three.txt

“MoVe”

#####And delete it:

rm three.txt

“ReMove”

#####Remove all files and folders without prompting and with no chance of recovery:

rm -rf .

“ReMove Recursively and Forcefully” everything in your current working directory. Don’t do this. Instead, mkdir ~/tmp and mv anything you no longer want to there.

#####Remove a directory:

rmdir things

“ReMove DIRectory” (you need to empty it first)

#####Put some text into a file:

echo "hello" > greet.txt

#####And display the contents:

cat greet.txt

“conCATenate and list”

#####Complete the name of a file without having to type it all:

touch afilewithalongname
cat af<tab>

(i.e. use the tab key)

#####Create a file within a folder within a folder:

mkdir one
mkdir one/two
echo "hello" > one/two/three.txt

#####Read its contents:

cat o<tab><tab><tab>

(i.e. use the tab key three times in succession)

#####Cycle through previously-entered commands:

Use the up and down arrow keys

#####Edit a previously-entered command:

Use the left and right arrow keys

#####Run some python code:

echo "print 'hello world'" > hello.py
python hello.py

#####Enter the Python shell:

python

#####Leave it again:

Ctrl-d

exit()

#####Install the beautifulsoup4 Python module:

pip install beautifulsoup4

Or, if your user account does not have full access rights to read and write files:

pip install --user beautifulsoup4