File Extensions Shell Help

Table of contents

1. Introduction

File Extensions Shell is the file type associations viewer, file finder, mass file extension changer, and file processing framework.

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2. Installation and removal

Administrative rights are required to perform installation and removal.

Uninstalling previous version is not necessary but recommended in order to remove registry entries that might have become obsolete in new version.

Automatic Installation

Use the provided installer to install and remove the product. Uninstallation preserves the existing extension descriptions.

Manual Installation

Copy the product's file to desired location and register it with the regsvr32 utility:

regsvr32 filext.dll

To uninstall the product, run regsvr32 with the -u option:

regsvr32 -u filext.dll

then delete the file. You may need to logoff prior to deleting as the shell extension modules are usually locked by shell.

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3. File extension descriptions

File extension description is a regular file which conveys information about a certain type of file. An extension description file has extension .filext (not shown in Windows Explorer), and its name matches the extension of represented file type. For example, the extension description file txt.filext represents the .txt type of files.

The name of a *.filext file may contain a dot; in such case the dot and the text after it is ignored and the text before dot is considered to be the extension name. For example, the file named txt.this describes the text files.filext behaves identically to a file named txt.filext.

This allows to give more descriptive names to the *.filext files. This is particularly useful when using the file processing framework.

Creating file extension descriptions

Use one of the following methods:

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4. Viewing file type associations

You need to create an extension description in order to view associations for an extension. See File extension descriptions for how to create one. The information about the extension's associations is reported via the custom columns in detailed view of Windows Explorer, as well as via the tool tips and Details pane (pic. 1). The information consists of:

To display the custom columns, from the menu View click Choose details... and check the following columns:

The names of the columns start with a dot, providing mnemonic connection with file extensions.

Pic. 1. File type associations view

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5. Finding a program associated with an extension

Right-click an extension description file and from the context menu click Find associated program. A new Explorer window will open showing the executable file used to open files having the selected extension.

You can also start the associated program by clicking Start associated program.

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6. Opening registry key for an extension

Right-click an extension description file, then expand Open registry key and click Extension or Class to start registry editor opened at the respective key.

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7. Bookmarking file extensions in Registry Editor

File extensions can be bookmarked in Registry Editor. Click Bookmark in Registry Editor from the context menu of the file extension description files, then open Registry Editor to navigate between the file extension keys without having to open separate Registry Editor window for each extension.

In addition to the extension's key the key of the extension's class is bookmarked, if exists.

The bookmarks are stored in the following registry key:

Note This operation deletes existing bookmarks.

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8. Viewing information about extension on the Internet

Viewing information about extension in a web browser

Right-click an extension description file, then expand Query Internet database and select one of the listed web sites to query for the information about the extension.

Viewing information about extension in a preview pane of Windows Explorer*

Select an extension description file to query a web site and display its response in a preview pane. The web site to query is marked with bullet point in Query Internet database menu. To change the web site click the corresponding menu item while holding <Ctrl> key. To switch the function on/off click Preview item.

*Requires Windows Vista or later

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9. Finding files of certain type

Note: this feature is supported only on Windows Vista and later systems.

To search a folder for files having specific extensions, select and right-click example files (see below), then from the context menu click Search for extension(s) here (pic. 2).

A separate Windows Explorer window will open showing the files found in the current folder.

To search a folder other than current, drag example files with the right mouse button and drop them on the folder which you want to search, then from the context menu click Search for extension(s) here (pic. 3).

Example files

An example file can be an extension description file (*.filext) or any file having extension:

So, if an example file is exe.filext or regedit.exe, then the *.exe files are searched for.

Pic. 2. Searching for *.exe in C:\Windows

Pic. 3. Searching for *.exe in C:\Program Files

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10. Changing extensions of files

Select the files for which you want to change extensions, and drag-and-drop (or copy-and-paste) them onto a file extension description file, which describes the desired new extension for the selected files. The selected files will be renamed to have the chosen extension.

If renaming would result in overwriting existing files, then such files are not renamed.

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11. File processing framework

Processing a file creates a copy of the file which differs from the original in some way; alternatively, the file is altered in place without creating a copy. You initiate processing by dragging and dropping a file to an extension description file (*.filext) which contains a script that does the processing.

Script example

The example presents the script which converts graphics files from one format to another (BMP in this case) using the convert tool from ImageMagick graphics processing package.

Pic. 4. Menu shown after a picture file is dropped onto a "bmp.filext" file

Script format

The script for the menu shown on the screenshot is reproduced below. To try it copy and paste it into a file named bmp.filext. The file must be saved in UTF-8 encoding. You may need to adjust the path to convert.exe.

Text=Convert to '<TargetExt>' format
Command="C:\Program Files\ImageMagick\convert.exe" "<SrcPath>" "<SrcDrive><SrcDir><SrcName>.<TargetExt>"

Text=Convert to '<TargetExt>' format and make monochrome
Command="C:\Program Files\ImageMagick\convert.exe" -monochrome "<SrcPath>" "<SrcDrive><SrcDir><SrcName>.<TargetExt>"

The script defines two menu items: one to convert an image to another format (determined by the output file's extension) and the other to convert an image and additionally make it monochrome. The first menu item is the default which means that its command executes when a file is dragged with the left mouse button.

Each section of INI file corresponds to a menu item of a drag-and-drop menu. The structure of a section is described below:

[Section name] Can be any text.
Default Specifies if the menu item is default (= 1) or non-default (= 0). The default command is executed when a file is dragged with the left mouse button.
Text A text that appears on the menu item.
Command A command that is executed when the menu item is clicked.

The Text and the Command parameters can use macros which expand to the path of a dropped file and to the parts of that path. The macros are denoted with the angle brackets. The list of the supported macros follows:

Macro name Description Example
<SrcPath> Full path to the dropped file C:\some\dir\picture.jpeg
<SrcDrive> The drive of the dropped file C:\
<SrcDir> The directory path, excluding the drive part, from where the dropped file was dragged some\dir\
<SrcName> The name of the dropped file, without extension picture
<SrcExt> The extension of the dropped file, without dot jpeg
<TargetExt> The name of the *.filext file before the first dot bmp
<TargetDescr> The part between name and extension of a *.filext file (if any) 48x48 (see example below)

The Text parameter can only use the <TargetExt> and <TargetDescr> macros. The Command parameter can use any one of the described macros. In this example, because the converted file is dropped onto a bmp.filext file, <TargetExt> becomes "bmp".

The Command parameter can also use the operating system environment variables (denoted with leading and trailing percent character).

Note that the "<SrcPath>" is equivalent to the "<SrcDrive><SrcDir><SrcName>.<SrcExt>".

Instead of using <TargetExt> macro one could simply write "bmp"; however, because the target extension is not specified explicitly, the script can be copied without changes to other *.filext files, for example "png.filext" or "gif.filext", making those files convertors to the respective formats.

The <TargetDescr> macro utilizes a descriptive name feature. The following example shows the use of a <TargetDescr> macro.

Text=Convert to '<TargetExt>' format and resize to <TargetDescr>
Command="C:\Program Files\ImageMagick\convert.exe" -resize <TargetDescr> "<SrcPath>" "<SrcDrive><SrcDir><SrcName>_<TargetDescr>.<TargetExt>"

Assuming that the script above is placed into a bmp.48x48.filext file, it converts a dragged file to BMP format and resizes it to be of 48x48 pixels size. The output file will have "48x48" suffix appended to its name.

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12. Copying file mask

The command Copy mask from the context menu of a file extension description copies to clipboard a mask which specifies the files having the extension. For example, if exe.filext file is selected then the mask *.exe is copied to clipboard.

If more than one extension description file is selected then their masks are separated with semicolon. For example, if exe.filext, bat.filext and cmd.filext files are selected then the text *.exe;*.bat;*.cmd is copied to clipboard.

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13. Wiping out

File Extensions Shell installs disk cleaner which is accessible through standard Disk Cleanup utility. It allows to delete all extension descriptions on selected drive.

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14. Getting further help

You can send questions and feedback by e-mail: support (at) evilapp (dot) com,

or via Twitter:

Follow @evilapp to receive notifications about new product releases.

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15. Version history

version 1.3 released 09-Dec-2017
File extensions can be bookmarked in Registry Editor.
version 1.2 released 19-Jun-2017
Implemented file processing framework.
Added Copy mask command.
version 1.1 released 25-Jul-2013
Display information about file extensions in a preview pane of Windows Explorer
version 1.0.1 released 16-Nov-2012
Maintenance release
version 1.0 released 07-Jun-2012
First release

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16. Disclaimer

The software is provided "AS IS" without any warranty, either expressed or implied, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose. The author will not be liable for any special, incidental, consequential or indirect damages due to loss of data or any other reason.

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