The Command Line Interface is powerful

A little bit of terminology

  • Command Line Interface (CLI): This is a user interface that lets you interact with a computer. It is a legacy from the early days of computers. Now a days computers have graphical user interfaces instead (MacOSX, Windows, Linux, …)
  • Terminal: It is a an application that lets you run a command line interface. It used to be a physical machine connected to a mainframe computer
  • Shell: It is the program that runs the command line. There are many different shells, the most common (an default on most system) being bash (Bourne Again SHell)

Why should I learn about bash !?

# Clone this repository
cd ~
mkdir github
cd github
git clone "https://github.com/brunj7/eds214-handson-cli.git"
cd eds214-handson-cli
ls
cd _data/babynamesbystate
pwd

# Do I have all the states?
ls *.TXT
ls *.TXT | wc -l

# Look at the files
head CA.TXT
tail CA.TXT

# Want to know the most frequent ones over all the years?
sort -k5 -n -t"," CA.TXT | tail


# Concatenate the files
touch baby_allstates.csv     # create an empty file
echo "state, gender, year, firstname, count" > baby_allstates.csv  # add the header to the file
cat *.TXT >> baby_allstates.csv    # append the content of the files to the csv file

Did you know you can actually run Rfrom the command line:

R    # (ctrl + D to get out of it)

Or an R script:

Rscript 10min-loop.R   # (ctrl + C to kill the process)

And yes, you can run python as well:

python   # (ctrl + D to get out of it)

But this is for next week 🙂

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