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}}