cygwin's chmod behaves as working, but it does not work

Question

My Cygwin installation is behaving strangely: chmod does not work.

[09:45 Administrator@DellIns14 ~] > ls -ls /usr/bin/chmod
64K -rwxr-xr-x 1 Administrator None 38K Feb  6  2012 /usr/bin/chmod

[09:47 Administrator@DellIns14 ~] > rm /tmp/example.sh
rm: remove regular empty file `/tmp/example.sh'? y
[09:48 Administrator@DellIns14 ~] > touch /tmp/example.sh
[09:48 Administrator@DellIns14 ~] > ls -ls /tmp/example.sh
0 -rw-r--r-- 1 Administrator None 0 Jul  8 09:48 /tmp/example.sh
[09:48 Administrator@DellIns14 ~] > chmod -v +x /tmp/example.sh
mode of `/tmp/example.sh' changed from 0644 (rw-r--r--) to 0755 (rwxr-xr-x)
[09:48 Administrator@DellIns14 ~] > ls -ls /tmp/example.sh
0 -rw-r--r-- 1 Administrator None 0 Jul  8 09:48 /tmp/example.sh
[09:48 Administrator@DellIns14 ~] >

Note that the directory is writable, as the file is created.

When I look at this directory from a windows perspective, it is reported as read-only (even after I change it to read-write, it reverts to read-only).
Screen-captures are at cygwin's /tmp is read-only in windows, and cannot be changed to read-write

Can you suggest how to debug/solve?

Environment:
Windows 7, Cygwin 1.7.29(0.272/5/3) i686

Answer 1

Kudos to this answer https://stackoverflow.com/questions/25730041/updating-file-permissions-with-git-bash-on-windows-7 contents pasted below

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You are probably using NTFS or FAT32 on Windows, and those filesystems do not support the executable permission. Instead, cygwin looks at the file name and contents to determine whether it's executable:

Files are considered to be executable if the filename ends with .bat, .com or .exe, or if its content starts with #!.

So you should make sure that the bash file starts with a shebang. Then, you should be able to just execute the file, disregarding the permission output of ls.

Answer 2

I was unable to chmod until I found that /etc/fstab contained:

none /cygdrive cygdrive binary,noacl,posix=0,user 0 0

but needed to be:

none /cygdrive cygdrive binary,posix=0,user 0 0

After closing all open Cygwin processes and restarting, all worked.

Answer 3

I found This Answer helpful.

Besides normal POSIX permissions that contoll owner, group, other access, the file permission in Cygwin may also be affected by Windows ACL.

In your case, please try

ls -l /tmp/example.sh
getfacl /tmp/example.sh
setfacl -b /tmp/example.sh
ls -l /tmp/example.sh
chmod -v +x /tmp/example.sh
ls -l /tmp/example.sh