A command line program to get and set* any file property exposed by the Windows property system.
* For those properties that are read-write and supported for a file type.
The Windows property system provides a generic interface to access file system and file metadata properties. Almost everything about a file that you can see, and where possible change, via Windows Explorer is exposed through the property system. TouchProp uses this programmatic interface to provide a means of reading and writing these properties from a command line program.
You can find more information on the Windows property system here.
The following command:
TouchProp MyPhoto.jpg System.Comment
will output the Comments property of the file MyPhoto.jpg.
While the following command:
TouchProp MyPhoto.jpg System.Comment "A great photo"
will change the Comments property of the file MyPhoto.jpg to: "A great photo".
Similarly, the following command will change the jpg file's "Date Taken" property to 11:22:33 25 December 2001
TouchProp MyPhoto.jpg System.Photo.DateTaken "2001/12/25:11:22:33.456"
The names "System.Comment" and "System.Photo.DateTaken" in the examples are known as the canonical property name. You can find information on canonical names here.
The following command will output a list of all the possible properties available on your system.
This is useful because the property system is extensible by third party products, and different versions of Windows may support different properties, though the most common are likely to be available on any supported version of Windows.
It's probably easiest to deal with this list by redirecting the output to a file:
TouchProp -listprops > properties.txt
and then loading the output file into your favourite spreadsheet program such as Microsoft Excel. It's a tab delimited file, so should import easily into the spreadsheet.
Once loaded into a spreadsheet, each row contains the following columns:
Note that the canonical name must be spelled correctly with the correct case. "system.author" will not work, it has to be "System.Author".
NOTE: The following lists are types that I've encountered in testing, others may be listed on your system.
|Listed as||Description||Output example||Input format/example|
|IntN||1-8 byte signed integer number||1234 [-1234]||1234|
|UIntN||1-8 byte unsigned integer number||5678||5678|
|RealN||Floating point (real) number||12.34||12.34|
|Boolean||Boolean value||Depends on the specific property||Depends on the specific property|
|Filetime||Date+time timestamp||Your locale date/time format||yyyy/MM/dd:HH:mm:ss.fff
yyyy: 4 digit year
MM: 2 digit month
dd: 2 digit date
HH: 24h hours
fff: thousandths of a second
|Vector of ...||The property is multi-valued||Value1;Value2;Value3||Value[;ValueN]|
All properties are not applicable to all file types.
If a file doesn't have a value for a property, TouchProp outputs: "The property value is empty".
If a property isn't applicable to the file type, TouchProp outputs: "Failed to set the property value. The property may not be applicable for the type of file."
The list from the -listprops option will show lots of properties that have types that are not currently supported by TouchProp. For example:
|VT_STREAM||The name of the stream follows|
|VT_CLSID||A class ID|
There's currently nothing TouchProp can do with these properties. If you encounter one of these (or some other) that you think would be useful, please let us know.
If you're not familiar with handling timestamps in PowerShell, here's some information and examples that I've found useful to know.
The following examples have TouchProp.exe in the current working directory and the TestPhoto.jpg file in the parent directory.
$dtVar=Get-Date(.\touchprop ..\TestPhoto.jpg System.Photo.DateTaken)
Many properties can only be discrete enumerated values; they are are often (unsigned) integer value types, but are output as one of the enumeration names shown for the property via the -listprops option.
For example, the System.Photo.Contrast property may be output as "Normal", "Soft", or "Hard". You can modify the value by using the value (0, 1, 2) or by the corresponding enumeration output name. Note that if you use the name, it must match exactly, so for this property, "Soft" would be correct, but "soft" would result in an error.
Some property values have "ranged" enumerations - such as date/times, allowing you to use values such as "Yesterday", or "Earlier this month", but they are not precise times, so I think you'll find they're of limited practical use.
Many properties can have multiple values, for example, the System.Author (Authors) property is a multi-valued string property. If you display it using:
TouchProp MyPhoto.jpg System.Author
If the file has that property, TouchProp might output something like this:
David Lowndes; Julie Lowndes
To change the values, you can enter the following command:
TouchProp MyPhoto.jpg System.Author "Author1 Name[;AuthorN Name]"
i.e. repeat the section inside  for each value and each value is separated with a semi-colon ';'
Some properties may apparently be written OK ,with no problem is reported, but the underlying value doesn't change. For example, changing System.GPS.LongitudeDenominator on a JPG never seems to change the values.
This is an early public release to get your feedback on this program. I've developed and tested it against a variety of files, but it now needs more people to try it. There's likely to be things that I've forgotten to write about here and things that may not work correctly, so please let me know via email of anything you encounter that's not covered in this document. Equally valuable to me is knowing what you're doing with it so that I can make it better suit your needs, so again, please let me know.
Thanks for your feedback.