What does the following permissions prw-rw-rw mean and how do I set this permission

[Virginia OToole]

I am using the following command to compress a file that is being exported in Oracle.

/bin/compress < /lrg01/export/exp_pipe > /lrg01/export/chprod_fullexp.dmp.Z &

The file doesn't appear to be being compressed and the export fails because of a file being larger than 2G.

We have an identical script running on another machine that works. The only difference is the permissions on the exp_pipe file is prw-rw-rw. I am wondering if this is the cause of my problem. What does the "p" mean and how can I change the permissions on the problem file to
include the "p"

[CA538024 · Accepted solution]

Hi Virginia,

Your question would be better served if you posted in the HP-UX forum of the ITRC. Here's the link to that forum:

http://forums.itrc.hp.com/cm/

You'll find an hp-ux option there; that's where I'd head if I were you.

Good luck!

Kathy

[Moderator edit: The above link is no longer valid.]

[CA486125]

That's okay Kathy, I'll handle it.

The p stands for pipe, a special type of file. Suggest you go to www.docs.hp.com and search on the word pipe and read up. There is no good way to change the file *type*.

- regular file
d directory
b block type special file
c character type special file
l symbolic link
p pipe
s socket


Here is a desction of a pipe file

"A pipe provides a method to take output from one process and use it as input to another process. The HPPIPE intrinsic creates a new file type object called pipe for this purpose. It provides a one-way flow of data. After creating a pipe file type object, the HPPIPE intrinsic returns both read-access and write-access file numbers. Related processes can access the pipe.

Data can be written to the write-end and read from the read-end of the pipe. The data is accessed in a first-in-first-out manner, or FIFO.

A pipe file does not have a name associated with it and is not inserted into any directories upon creation. After the final close of a pipe file, the file is deleted. Pipe files are treated as new files. "

[Moderator edit: Removed the broken link. Please refer to https://support.hpe.com/]

[BR63572]

Hi,

to create the pipe, issue the command

mknod exp_pipe p

to change the permissions to rw-rw-rw- issue

chmod 666 exp_pipe

The Oracle export should write to this outputfile (exp_pipe) while the compress is reading from it and writing the finaly compressed file.

Since 2GB limit should not really be a problem today, you should check out "ulimit" in the shell that does the export and may be adjust it.

Hope this helps
Volker

[BR8935]

Hello Virginia,

to me it seems everything is ok about the pipe, but the file-system where you are to store the output of that command line, needs to be mounted with the option "-o largefiles" to be able to store a file bigger than 2GB!
You get the filesystem's name wou are working in with:
devnm $PWD

and then you can "grep" for that device name in "/etc/mnttab" (a file which does contain the information about all currently mounted filesystems).
I guess there is no "largefiles" option, yet.
Hence you will have to "umount" that filesystem, modify the "/etc/fstab" (that's the file containing the definitions what to mount and how to do it) and then you can mount it again with "mount -a" (you have to be "root" to this, of course).

HTH,
Wodisc