What is a holey file?

Posted on 1997-10-12
Last Modified: 2011-09-20
What is it? Why do they exist? Why I can't handle them as other files?
Question by:jlms
  • 3
  • 2

Expert Comment

ID: 2007394
"holey" file ? are you sure you got that right ?


Author Comment

ID: 2007395
I think so...

Expert Comment

ID: 2007396
Where did you get that info ? what OS ? ....
Free Tool: Port Scanner

Check which ports are open to the outside world. Helps make sure that your firewall rules are working as intended.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.


Accepted Solution

rembo earned 50 total points
ID: 2007397

When you talk about holey files, I'm assuming
that you're talking about files which were
creating with empty checks via lseek.  

These are stored in the filesystem using
only header info, not real disk blocks.  However,
if you try to put this on to a tape, especially
with dd or something like that, it will try to
write the actual blocks.  

For example, you could lseek forward 2GB in a file
and then write 1 character.  Your file size is then
huge, but it actually only takes up one disk block
(this is in UFS, not any old SVR4 system).  However,
older filesystems can figure this out.

Anyway, the deal is you need to be careful with things
that might try to map these headers to real data.

So, the deal is, try not to create holey files :)
but if you do, just know what you're doing with
them and how you move them.  Try to use tar and
modern, ufs or vxfs filesystems.  

If there's a specific application you're wondering
about, let me know.  I'd be happy to help.



Author Comment

ID: 2007398
I think I understand, and no, I don't have any application in particular in mind.

One last thing, how can I recognize one of this files?

Author Comment

ID: 2007399
I think I understand, and no, I don't have any application in particular in mind.

One last thing, how can I recognize one of this files?

Featured Post

Announcing the Most Valuable Experts of 2016

MVEs are more concerned with the satisfaction of those they help than with the considerable points they can earn. They are the types of people you feel privileged to call colleagues. Join us in honoring this amazing group of Experts.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
netstat -a in AIX unix 8 48
pauing printer deamon in AIX 10 63
Best way to handle awk return value 6 70
MarkLogic 1 89
Installing FreeBSD… FreeBSD is a darling of an operating system. The stability and usability make it a clear choice for servers and desktops (for the cunning). Savvy?  The Ports collection makes available every popular FOSS application and packag…
Why Shell Scripting? Shell scripting is a powerful method of accessing UNIX systems and it is very flexible. Shell scripts are required when we want to execute a sequence of commands in Unix flavored operating systems. “Shell” is the command line i…
Learn several ways to interact with files and get file information from the bash shell. ls lists the contents of a directory: Using the -a flag displays hidden files: Using the -l flag formats the output in a long list: The file command gives us mor…
Learn how to get help with Linux/Unix bash shell commands. Use help to read help documents for built in bash shell commands.: Use man to interface with the online reference manuals for shell commands.: Use man to search man pages for unknown command…

831 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question