Not sure whether this is the right place to post.
It may happen that one wants to check whether there are any duplicates of a selected file.
Whilst using Everything (Voidtools) v1.5 - See: Everything downloads
one might add a context menu item reading as follows:
"\path to everything-exe\Everything64.exe" -s* size:[getsize:"%1"] ext:[get-property:"%1","extension"]
Important: use the latest version...
[Example]
r-click file and select "Everything Find Dups..."
Nice. I find this very useful. 
Only one thing, could you also match the name?
Sorry for the late reply, I was out last week.
You mean to say, select file, find duplicate elsewhere?
Maybe you could try: "x:\path\Everything64.exe" -s file:exact:"%1"
Thank you, opw62. No problem, my post is only a few hours old. I have now added both versions. The algorithm seems to use rounded values, so that i find different small files, all having 1kb. In case i am looking for exact copies, i can use your second command now.
Just FWIW...
I created a context submenu with some Everything commands
Search duplicate file name:
"X:\Everythingpath\Everything64.exe" -s* file:#filename:"%1"
Search Everything:
"X:\Everythingpath\Everything64.exe" -s {file}
Search same date:
X:\Everythingpath\Everything64.exe" -s* dm:[formatfiletime:[get-date-modified:"%1"],yyyyMMdd\THHmmss.SSSSSSS]
Search dups of selected folders:
X:\Everythingpath\Everything64.exe" -s* folder: size:[get-property:"%1","total size"]
Search in X:\Photos:
X:\Everythingpath\Everything64.exe" -filter "X:\Photos" -s {file}
Search same size:
"X:\Everythingpath\Everything64.exe" -s* size:[getsize:"%1"] ext:[get-property:"%1","extension"]
Thanks, looks very useful.
How easy would this be to add? Could you perhaps write a small guide? 
Try this button. You will have to edit each menu item (Alt-click on it) to set the right paths for your machine. To add that menu, go into the edit mode and drag it to a toolbar.
Various Everything Searches.dcf (2.1 KB)
As for finding duplicates, one might also consider using: dupe:size;dm;name
in the search box (or even better, add a filter with this search).
Or just: dupe:size;dm which will show possible duplicates with a different file name (due to file renaming)
Thank you guys for all this, invaluable information !!