Cygwin Path and Windows Path Conversion
The filename path issue between unix and Windows can be complex.
In general, when you are in Cygwin, always use unix-style path, for example,
/something/something. When you need
For example, when i started to use Cygwin, had a problem that caused me few hours. I have a python program that makes a system call of imagemagick's
convert command. This all works fine in OS X. When trying to run it on Windows with Cygwin, i simply changed the input paths from
C:/Users/xah/web/. This does not work. After some hours of looking, here's some detail:
When in Cygwin terminal, the following does not work:
# cygwin complains cannot find the second file # convert: unable to open image `/Users/xah/x2.jpg': No such file or directory. convert C:/Users/xah/x.png C:/Users/xah/x2.jpg convert "C:/Users/xah/x.png" "C:/Users/xah/x2.jpg" # complains cannot find the first file convert /Users/xah/x.png ~/x2.jpg convert "C:/Users/xah/x.png" /Users/xah/x2.jpg convert /Users/xah/x.png /Users/xah/x2.jpg convert /Users/xah/x.png x2.jpg
The following creates the image, but the result image is bad.
# creates image, but bad img data convert C:/Users/xah/x.png "C:\Users\xah\x2.jpg" convert C:/Users/xah/x.png C:\\Users\\xah\\x2.jpg # this one creates image in the in current dir as Usersxahx2.jpg convert C:/Users/xah/x.png C:\Users\xah\x2.jpg
The following works:
convert "C:/Users/xah/x.png" ~/x2.jpg convert C:/Users/xah/x.png ~/x2.jpg convert C:/Users/xah/x.png /cygdrive/c/Users/xah/x2.jpg convert /cygdrive/c/Users/xah/x.png /cygdrive/c/Users/xah/x2.jpg
Here's some lesson learned:
- When you are in Cygwin terminal, you are running bash. That means, paths like “~” are interpreted by bash first. It also means, backslash means quoting the next char, and double straight quotes quotes your string, just as bash in unix.
- Cygwin provides a map from Windows path to unix path, by “mount”. For example,
C:/somethinggets mapped to
- Not sure what mechanism
/cygdrive/cis mapped to the disk. Similarly, how
/usr/binactually refers to the real location repesented by the Windows syntax
C:/cygwin/usr/bin. Probably some Cygwin internal.
- When in Cygwin, stick with unix style path. When you need
- Unrelated to Cygwin, but Windows's API actually understand forward slash for path separator, as well as path without a drive letter. It's just that some apps such as cmd.exe doesn't deal with it. Windows PowerShell does. (see Wikipedia's “path” article on this.)
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