tldr/pages/common/mlr.md

# mlr

> Miller is like `awk`, `sed`, `cut`, `join`, and `sort` for name-indexed data such as CSV, TSV, and tabular JSON.
> More information: <https://johnkerl.org/miller/doc>.

- Pretty-print a CSV file in a tabular format:

`mlr --icsv --opprint cat {{example.csv}}`

- Receive JSON data and pretty print the output:

`echo '{"hello":"world"}' | mlr --ijson --opprint cat`

- Sort alphabetically on a field:

`mlr --icsv --opprint sort -f {{field}} {{example.csv}}`

- Sort in descending numerical order on a field:

`mlr --icsv --opprint sort -nr {{field}} {{example.csv}}`

- Convert CSV to JSON, performing calculations and display those calculations:

`mlr --icsv --ojson put '${{newField1}} = ${{oldFieldA}}/${{oldFieldB}}' {{example.csv}}`

- Receive JSON and format the output as vertical JSON:

`echo '{"hello":"world", "foo":"bar"}' | mlr --ijson --ojson --jvstack cat`

- Filter lines of a compressed CSV file treating numbers as strings:

`mlr --prepipe 'gunzip' --csv filter -S '${{fieldName}} =~ "{{regular_expression}}"' {{example.csv.gz}}`