Open documents from Windows with Cygwin programs directly

Question

Is it possible to open a document by using the Windows 10's "open with" feature with a program that comes with Cygwin, e.g. Zathura?

This one with a Cygwin program.

First attempt: try to simply use the Cygwin program under Windows directly, i.e. the executable in C:\cygwin64\bin (in case of the standard install path).

Regardless of the "open with" problem, directly opening a Cygwin program often doesn't work well except for the most simple programs (no login shell is run first!).

So, starting the Cygwin X server, setting the Windows system environment variable DISPLAY (this gets passed through) to :0.0, using "open with" on C:\book.pdf and choosing C:\cygwin64\bin\zathura.exe makes Zathura open the GUI window. But we get the error:

error: Unknown file type: 'cannot open `/cygdrive/c/Windows/system32/C:\book.pdf'    
(No such file or directory)'

❓

Obviously, something goes wrong with the path here.

Second attempt: work around the problem by using a Windows shortcut with the target:

C:\cygwin64\bin\bash.exe -l -c 'zathura "`cygpath "$0"`"'

At least that works for drag and drop in the Windows explorer. But again not with "open with".

As a minimal example create a Windows shortcut emitpath.lnk with the target:

C:\cygwin64\bin\bash.exe -l -c 'echo "`cygpath "$0"`" > out.path'

It works as expected again with dragging & dropping the document onto the shortcut: a file in the Cygwin home out.path is created and the "cygwin-ified" path of the document is written into it. We got very close.

But, alas, with "open with" it does not work; nothing happens.

So how to use "open with" with a Cygwin program on Windows 10?

There must be an easier way than to create an executable wrapper.

Answer 1

Make a batch file like:

@echo off
D:
chdir D:\cygwin64\bin
set A=%1
bash --login  -c "/usr/bin/echo $(cygpath  $A)"
pause

In the root directory of Cygwin should be present a Cygwin.bat to be used as base.
Put the link to the batch file in the SendTo Folder

Now when I send a picture from my Pictures folder, I have in a new CMD window:

/cygdrive/c/Users/Marco/Pictures/img250.jpg
Drücken Sie eine beliebige Taste . . .

The last is Press any key in German.
From here you can modify the batch to run any cygwin program you want.

If you plan to use the X server, it is probably better to have the Xwin server already running due to possible timing problem in the execution.

Answer 2

The problem with matzeri's solution is that it only works for the most sane filenames. A white space in the filename already breaks it.

Remember, if C:\book 1.pdf is the document to be opened, we want to end up with a string where on the bash side the escaping is correct - like this:

"/usr/bin/zathura \"$(cygpath 'C:\book 1.pdf')\""

But Windows passes the document path as an argument to a batch-script in two different ways:

• "open with": always double-quoted.
• "drag & drop": only sometimes double-quoted (when white spaces are present).

Because of the very abstruse escape rules of the batch language, it's probably better to use a lot of intermediate variables to build the string; otherwise you'll get insane.

We can use:

• ^ escapes the ". But only in unquoted strings, see here!

• set x=%x:"=% is a substitution of " by nothing in the string in variable x.

• The single quote ' is a normal character and does not need to be escaped.

So the following batch file does the job:

@echo off
C:
cd C:\cygwin64\bin
set pdfpath=%1
set pdfpath=%pdfpath:"=%
set cygpart=$(cygpath '%pdfpath%')
set fullcmd=/usr/bin/zathura \^"%cygpart%\^"
bash -l -c "%fullcmd%"
pause

There may be some strange filename which still breaks it. But at least it works for all somewhat normal filenames, including ones containing white spaces, parentheses, brackets.