Check if folder is a mounted remote filesystem

As Stephane says "there is no universal Unix answer to that".

The best solution I have found to my question:

df -P -T /my/path/to/folder | tail -n +2 | awk '{print $2}'

will return the filesystem type, for example: nfs or ext3.

The -T option is not standard, so it may not work on other Unix/Linux systems...

According to Gilles' comment below: "This works on any non-embedded Linux, but not on BusyBox, *BSD, etc."

You could use GNU stat.

%m to find out the mountpoint.

$ stat --format=%m /usr/src/linux
/usr/src

%T (in file-system mode) to find out the name of the file system.

$ stat --file-system --format=%T /usr/src/linux
reiserfs

Thus you know that /usr/src/linux, on my system, is stored in a filesystem that is mounted on /usr/src and has the filesystem type reiserfs.

Also refer to man stat for further reference. It's a very versatile command, useful almost always when you need info about files and don't want to fall back to grep | awkwardness.

mount -l and use grep, sed, or awk to find the line that refers to the directory in question.