csv-lookup is a Node.js command line app that adds or replaces a column value in a source CSV file by looking up a value in a lookup CSV file.

npm i -g csv-lookup

The following replaces the PersonId column in source.csv with the value of the Name column in lookup.csv where PersonId from source matches Id from lookup.

csv-lookup.js -s PersonId \\
  -l lookup.csv -k Id -v Name \\
  < source.csv \\
  > output.csv

For extended help, type the command name with no arguments.

You can optionally add a column to the source.csv instead of replacing the value of the column.

You can also optionally remove rows where there is no match.