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71 lines
1.8 KiB
Markdown
71 lines
1.8 KiB
Markdown
---
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jupytext:
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text_representation:
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extension: .md
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format_name: myst
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kernelspec:
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display_name: Bash
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language: bash
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name: bash
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---
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# Lesson 2: Piping commands
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:::{admonition} Lesson is a work in progress
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:class: warning
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This lesson is not complete. Stay tuned!
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:::
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We've been using one command at a time, but what if we want to use multiple?
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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.
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## Selecting the columns
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Take a brief look at `qsv select`:
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```{code-cell}
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:tags: ["scroll-output"]
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qsv select -h
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```
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There are several ways to select the columns we want. Let's take a look at the headers first:
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```{code-cell}
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:tags: ["scroll-output"]
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qsv headers fruits_extended.csv
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```
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We only want data within the `fruit` and `availability` columns. Let's try selecting the data within those columns:
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```{code-cell}
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:tags: ["scroll-output"]
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qsv select 1,4 fruits_extended.csv
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```
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Great, we got the column data that we're looking for. But how do we run this data through `qsv table`?
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## Command redirection
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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.
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<!-- Add link to appendix or do a dropdown or continue lesson and explain each one. -->
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<!-- Improve flow for previous sentence to next one or modify flow. -->
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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`:
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```{code-cell}
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:tags: ["scroll-output"]
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qsv select 1,4 fruits_extended.csv | qsv table
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```
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Now we've got what we were looking for!
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:::{admonition} Exercise is a work in progress
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:class: important
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The exercise for this lesson is not available yet. Stay tuned!
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:::
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