File Descriptor Help


 
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# 1  
Question File Descriptor Help

What is a file descriptor in Unix??

How to find a file descriptor of a file in Unix??

Does it have anything to do with the Inode numbers??
# 2  
file

Rathore
u c an use stat structure and find it
arun
# 3  
Mr Arun Thanks for ur reply.

But i dint get it still.

Where is this stat structure located. Is it a command.
If it is it does n't run in SCO unix.

if it is a file where is it located.
# 4  
If you are familiar with UNIX I/O redirection, syntax similar to the following should not be new to you:
command > file 2>&1
When command runs it sends "normal" output to file, and any error messages generated by command are also written to file. "2>&1" handles the latter.

The 2 and 1 are file descriptors. So what's a file descriptor?

When a UNIX program wants to use a file, it must first open that file. When it does so, UNIX will associate a number with the file. This number, which is used by the program when reading from and writing to the file, is the file descriptor.

A typical UNIX program will open three files when it starts. These files are:

- standard input (also known as stdin)
- standard output (also known as stdout)
- standard error (also known as stderr)

Standard input has a file descriptor of 0, standard output uses 1, and the number 2 is used by standard error.
 

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