Related tools

Learning outcomes

• Hear about the tools similar to awk

For teachers

Teaching goals are:

• Show the tools similar to awk

Lesson plan:

• 5 mins: prior knowledge
• 5 mins: presentation
• ? mins: challenge
• 5 mins: feedback

Overview

In this session, we learn about the Linux tools related to awk.

flowchart TD

  classDef focus_node fill:#fff,color:#000,stroke-width:4px

  awk:::focus_node
  cut
  grep
  sed
  tr
  wc

  regexps[Regular expressions]
  split_data_in_columns[Split data into columns]
  count[Count]
  replace[Replace]

  %% Tools
  awk --> |can do| regexps
  sed --> |can do| regexps
  grep --> |can do| regexps

  awk --> |can do| split_data_in_columns
  cut --> |can do| split_data_in_columns

  awk --> |can do| count
  wc --> |can do| count

  awk --> |can do| replace
  tr --> |can do| replace
  sed --> |can do| replace

Tool	Regular expressions	Split data into columns	Replace	Count
awk	Yes	Yes	Yes	Yes
cut	No	Yes	No	No
grep	Yes	No	No	Yes
sed	Yes	Yes	Yes	Yes
tr	No	No	Yes	No
wc	No	No	No	Yes

An overview what tools can do by themselves.

Note that most tools are not intended to do all by themselves. Instead, they are intended to do one thing well and be part of pipelines.

Exercises

See the exercise procedure.

Exercise 1: cut

Learning outcomes

• Use cut

Read:

• The top part of the Wikipedia about page on 'cut'

In a terminal, do:

wget https://raw.githubusercontent.com/richelbilderbeek/awk_course/master/data/diamonds_raw.csv

to download a file called diamonds_raw.csv.

Then, in a terminal, do:

• man cut
• cut -d "," -f 2 diamonds_raw.csv
• cat diamonds_raw.csv | cut -d "," -f 2

Express in your own words: what does cut do?

Exercise 2: grep

Learning outcomes

• Use grep

Read:

• The top part of the Wikipedia about page on 'grep'

In a terminal, do:

wget https://github.com/devstronomy/nasa-data-scraper/raw/master/data/csv/satellites.csv

to download a file called satellites.csv.

Then, in a terminal, do:

• man cut
• grep om satellites.csv
• cat satellites.csv | grep [^aeiou]om

Express in your own words: what does grep do?

Exercise 3: sed

Learning outcomes

• Use sed

Read:

• The top part of the Wikipedia about page on 'sed'

In a terminal, do:

wget https://www.gutenberg.org/cache/epub/1787/pg1787.txt

to download a file called pg1787.txt.

Then, in a terminal, do:

• man sed
• sed 's/Hamlet/Frederik X/g' pg1787.txt
• sed 's/Hamlet/Frederik X/g' pg1787.txt | awk '/Frederik X/'
• sed 's/Hamlet/Frederik X/' pg1787.txt | awk '/Frederik X/'

Express in your own words: what does sed do?

Exercise 4: tr

Learning outcomes

• Use tr

Read:

• The top part of the Wikipedia about page on 'tr'

Then, in a terminal, do:

• man tr
• echo "Hello" | tr -s e a
• echo "Hello" | tr -d e
• echo "Hello world" | tr -d aeiou

Express in your own words: what does tr do?

Exercise 5: wc

Learning outcomes

• Use wc

Read:

• The top part of the Wikipedia about page on 'wc'

In a terminal, do:

wget https://www.gutenberg.org/cache/epub/1787/pg1787.txt

to download a file called pg1787.txt.

Then, in a terminal, do:

• man sed
• wc pg1787.txt
• wc pg1787.txt --lines
• wc pg1787.txt --words
• awk '/Hamlet/' pg1787.txt | wc --lines

Express in your own words: what does wc do?