How to create a shortcut that opens Cygwin bash shell on a directory of the choosing (UNC especially)

From the manual,

When Bash is invoked as an interactive login shell, or as a non-interactive shell with the --login option, it first reads and executes commands from the file /etc/profile, if that file exists.

/etc/profile by default contains the following code:

# Make sure we start in home unless invoked by CHERE
if [ ! -z "${CHERE_INVOKING}" ]; then
  unset CHERE_INVOKING
else
  cd "${HOME}" || echo "WARNING: Failed attempt to cd into ${HOME}!"
fi

So one solution would be to create a Windows batch file that sets the environment variable CHERE_INVOKING before starting bash. That is not very neat.

Next,

After reading that file, it looks for ~/.bash_profile, ~/.bash_login, and ~/.profile, in that order, and reads and executes commands from the first one that exists and is readable.

These profile scripts by default execute your ~/.bashrc script if it exists. Putting cd - at the end of my .bashrc works for me (with the latest Console2 and Cygwin bash):

echo 'cd -' >> ~/.bashrc

BTW, I invoke Console2 (Console.exe) with no arguments - Windows Explorer ensures that it starts up in the directory that I right-clicked. I'm using XP but I doubt MS would change this behavior in later versions of Windows. I also leave the "startup dir" option blank for my Bash tab.

An msysgit git bash session uses the script share/WinGit/Git Bash.vbs, which doesn't access or modify the environment variable PATH (like it would in this unrelated vbs script, for instance)

A git bash session will simply add in front of your current PATH:

.:/usr/local/bin:/mingw/bin:/bin:

It is possible that the mingw session packaged with msysgit won't consider a bin from another mingw installation: you can check it by setting another (simpler) directory to your PATH and see if it is still visible in your git bash session. If not, then it is a more general issue which concerns all directories that you would add to the PATH.