How to write an applescript to hide a user specifid application?

Question

I want to write an applescript to take a command line argument (application name) as input and hide the application, so I tried the following script:
on run argv
          tell application "Finder"
                    set visible of process argv to false
          end tell
end run
However, when I tested it, it kept saying something like (my mac is Chinese...): "Can't convert <script> to Integer tpye." number -1700 from «script» to integer
does anyone know what the error was and how to fix it?
Thank!

Answer 1

The basic construct is a try/end try block which runs your own code when an error occurs rather than stopping your script.
An alternative when using do shell script is to suppress stdout and stderr so that errors are not returned to the application. Which you can do by appending ' > /dev/null 2>&1 &' to the end of the shell command.
Note, though, that your command will not work as written because 'choose folder' will return an alias object which can not be passed to a shell command as-is. Shell commands require unix-style paths for all file/folder parameters. Fortunately, AppleScript makes this easy by providing a POSIX path command which will convert an alias to a unix path. Additionally, since Mac paths can commonly include spaces and other non-shell safe characters, you may want to quote the path, too, like:
<pre class=command>set shell_script to "usr/local/bin/readpst -o " & quoted form of POSIX path of mbox_output & " " & pst_input & " > /dev/null 2>&1 &"</pre>