100.dathere.com/lessons/2/index.md

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Lesson 2: Piping commands

:::{admonition} Lesson is a work in progress :class: warning

This lesson is not complete. Stay tuned!

:::

We've been using one command at a time, but what if we want to use multiple?

For example let's say I want to only see what fruits there are and their availability from fruits_extended.csv in a nicely formatted table.

Selecting the columns

Take a brief look at qsv select:

:tags: ["scroll-output"]
qsv select -h

There are several ways to select the columns we want. Let's take a look at the headers first:

:tags: ["scroll-output"]
qsv headers fruits_extended.csv

We only want data within the fruit and availability columns. Let's try selecting the data within those columns:

:tags: ["scroll-output"]
qsv select 1,4 fruits_extended.csv

Great, we got the column data that we're looking for. But how do we run this data through qsv table?

Command redirection

If you're not sure what stdin, stdout, and stderr are then we recommend reading the "Command data streams (stdin, stdout, and stderr)" section in the Appendix.

For example let's say we want to display the previous output with qsv table. We can run the following to pipe the output into qsv table:

:tags: ["scroll-output"]
qsv select 1,4 fruits_extended.csv | qsv table

Now we've got what we were looking for!

:::{admonition} Exercise is a work in progress :class: important

The exercise for this lesson is not available yet. Stay tuned!

:::