check absence of file with "passes shell script"

Hi,
I want a rule to be executed only if a file in a specific folder and its subfolders (not the matched folder) does not exist.
In Terminal, i can check it with:
find /path/to/file/ -name filename.pdf
How can this command be put in a "passes shell script"- script ?
Thanks for any help.
Graf Wetter
I want a rule to be executed only if a file in a specific folder and its subfolders (not the matched folder) does not exist.
In Terminal, i can check it with:
find /path/to/file/ -name filename.pdf
How can this command be put in a "passes shell script"- script ?
Thanks for any help.
Graf Wetter