# List files

List files (\*.list) are similar to conc files in that they list the files that are related to a single analysis. Whereas conc files list only one type of image files that are to be concatenated, list files enumerate different types of files necessary for a specific analysis grouped by sessions (or subjects). Information on each session starts with keyword `session id:` followed by a unique identification code for that session. The following lines then list paths to all the files that relate to that session. The files can represent different information and are preceded by a keyword specifying what information the file holds. Keywords currently in use are:

* `file:` — the file listed is an image file (can also be a conc file)
* `roi:` — the file listed is a session-specific ROI mask image file
* `fidl:` — the file listed is a fidl file corresponding to the listed image file(s)
* `glm:` — the file listed holds results of GLM analyses with additional metadata

More than one image file can be listed in which case the image files will be concatenated in the order listed.

## Example

Here is an example content of a list file:

``` bash
session id: s03
    roi:/data/study1/session3/segmentations/freesurfer/mri/aseg.nii.gz
    file:/data/study1/session3/bold/wm-run.conc
    fidl:/data/study1/session3/task/wm.fidl
session id: s03
 id: s07
    roi:/data/study1/session7/segmentations/freesurfer/mri/aseg.nii.gz
    file:/data/study1/session7/bold/wm-run.conc
    fidl:/data/study1/session7/task/wm.fidl
...
```

List files are used in analyses that are optimized to run on group data and provide an efficient way to list all the relevant information for the entire group, enabling to run the analysis and provide group results in a single command call.

To ease generation of `.list` files, a [`create_list`](../../api/gmri/create_list.rst) QuNex command is available. The command can be called with a set of parameters that allow flexible generation of `.list` files for a specific set of sessions and the desired set of files. For details, please consult in-line documentation by running `qunex ?create_list`.