File_I/O Commands

[Brian K. White]

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)

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