The method dup2() duplicates file descriptor fd to fd2, closing the latter first if necessary.
Note ? New file description would be assigned only when it is available. In the following example given below, 1000 would be assigned as a duplicate fd in case when 1000 is available.
Following is the syntax for dup2() method ?
This method returns a duplicate of file descriptor.
The following example shows the usage of dup2() method.
import os, sys
# Open a file
fd = os.open( "foo.txt", os.O_RDWR|os.O_CREAT )
# Write one string
os.write(fd, "This is test")
# Now duplicate this file descriptor as 1000
fd2 = 1000
# Now read this file from the beginning using fd2.
os.lseek(fd2, 0, 0)
str = os.read(fd2, 100)
print "Read String is : ", str
# Close opened file
os.close( fd )
print "Closed the file successfully!!"
When we run above program, it produces following result ?
Read String is : This is test
Closed the file successfully!!