You could use incron (inotify cron).
Same idea as
cron, except that instead of being time-based, you define an
incrontab that specifies what command to run upon some given event in the filesystem.
incrontab in your case would look like:
/tmp IN_CLOSE_WRITE /path/to/someCommand $#
someCommand would be called whenever a file has been written and closed with the filename as argument (and
someCommand would need to check if it's been passed a file called
A note of warning though.
/tmp is world writable, so anybody and anything can write files there and can also create symlinks there. So it can cause you to overwrite any file you have write access to when you transfer that
myFile (using a symlink), or it can cause you to run another command than the one you expect (like a trojan). It would make more sense to put the file in a directory where only you have write access to.