# extract

## Overview

The tool extracts a copy of specified objects from a package and writes to a directory

## Example Usage

Extract subject `S1234` to `/path/to/outdir`

`squirrel extract <package> --object subject --objectid S1234 --outdir /path/to/outdir`

## Options

### --object

`--object <object>` can be one of the following

* package
* subject
* study
* series
* analysis
* intervention
* observation
* experiment
* pipeline
* groupanalysis
* datadictionary

### --outdir

`--outdir <outdir>` specifies a path to which the object(s) will be written. Filenames(s) will reflect the object IDs or names.

### --objectid

`--objectid <id>` specifies the ID or name of the object to extract. For example: subject with ID `S1234` or experiment named `MyExperiment`.

### --recurse

If specified, `--recurse` will extract all child objects of the specified object. If option is not set, only the specified object will be extracted.

### --subjectid

`--subjectid <id>` specifies the subject ID when extracting **study**, **series**, **intervention**, **observation**, or **analysis** objects.

### --studynum

`--studynum <num>` specifies the study number when extracting **series** and **analysis** objects. Must be used with `--subjectid` option.


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