File_I/O Commands

[Rodgers Hemer]

On Jan 1, 2011, at 3:43 PM, Brian K. White wrote:

> On 1/1/2011 5:11 PM, Rodgers Hemer wrote:
>> I would be most appreciative if someone would provide me a real world example of the File I/O open and write commands.  I have tried to follow the help pages for these commands but they are confusing with their repetitive use of "aa=" and none of my efforts pass the syntax check.
>> 
>> I want to create/open a file to which a single line consisting of a full path name of another file is written.  For example, create/open a new file named xxx in /u/appl/tmp/.  Then write the full path name of another file in the new file.
>> 
>> All help will be much appreciated.
>> 
>> Thanks
>> 
>> Rodgers Hemer
> 
> 
> N = "/path/to/some/file"
> H = open(N,"cw0t")
> D = "some data"
> x = writeline(H,D)
> x = close(H)
> 

Brian:

Thanks.  You did answer my question with the brief summary above.  To me, it is much clearer than the help files.  I know how to do the other file handling with filePro and shell scripts.  It was just filePro's file I/O syntax that confused me.

Rodgers Hemer

> But you didn't really say enough, and so this example, while perfectly 
> valid and real world, probably won't be much use.
> 
> Rather than spend the next half hour going over a bunch of possible 
> scenarios about what you might be really trying to do with the file, and 
> how best to deal with them, I've answered the question you asked, and 
> you'll have to ask a better question to get a better answer.
> 
> What is the file to be used for?
> Under what circumstances is this process that creates the file run? (a 
> user-initiated process? a root owned cron job? a wwwrun or nouser owned 
> cgi? etc)
> Under what circumstances is this process that reads the file run?
> (same examples as above)
> 
> These things determine what steps you need to take to deal with file 
> permissions, and discarding of the file when it's no longer needed.
> 
> The sample above will have the filepro clerk or report binary creating 
> the file, and doesn't try to delete the file since I'm assuming you need 
> some other process to read the file, and since filepro is creating the 
> file, only filepro or root will be able to delete the file later.
> 
> So the other process needs to be another filepro process, and "x = 
> remove(N)" should work to delete it, or if it's anything else it needs 
> to be root owned like a cron job. Otherwise you need to pre-create the 
> file with a system command before the open() command, and remove the "c" 
> from the open() options.
> 
> -- 
> bkw
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