# Common Workflow Language Integrations

## Simple operations

Simple NGLess operations can be performed through the [command line wrappers](command-line-wrappers.html), all of which have a CWL tool description.

## Automatic CWL export of NGLess scripts

An NGLess script that conforms to certain rules can be exported as a CWL tool using the –export-cwl option:

ngless script.ngl –export-cwl=tool.cwl

The rules are simple: the script must use ARGV for its inputs and outputs. For example, this is a conforming script:

ngless “0.8”

mapped = samfile(ARGV[1])

mapped = select(mapped, drop_if=[{mapped}])

write(mapped,

ofile=ARGV[2])

The resulting tool will take two arguments, specifying its input and output.