Working with CSV

How to:

Reading a CSV File Line by Line

while IFS=, read -r column1 column2 column3
  echo "Column 1: $column1, Column 2: $column2, Column 3: $column3"
done < sample.csv

Sample output:

Column 1: id, Column 2: name, Column 3: email

Filtering CSV Rows Based on a Condition

Using awk, you can easily filter rows. For example, to find rows where the second column equals “Alice”:

awk -F, '$2 == "Alice" { print $0 }' sample.csv

Modifying a Column Value

To change the second column to uppercase:

awk -F, 'BEGIN {OFS=",";} { $2 = toupper($2); print $0; }' sample.csv

Sorting a CSV File Based on a Column

You can sort a CSV file based on, let’s say, the third column (numerically):

sort -t, -k3,3n sample.csv

Using csvkit for More Complex Tasks

csvkit is a suite of command-line tools for converting to and working with CSV. It can be installed via pip.

To convert a JSON file to CSV:

in2csv data.json > data.csv

To query a CSV file using SQL:

csvsql --query "SELECT name FROM sample WHERE id = 10" sample.csv

Note: Installing csvkit requires Python and can be done using pip install csvkit.