Python method lseek() sets the current position of file descriptor fd to the given position pos, modified by how.
Following is the syntax for lseek() method −
os.lseek(fd, pos, how)
fd − This is the file descriptor, which needs to be processed.
pos − This is the position in the file with respect to given parameter how. You give os.SEEK_SET or 0 to set the position relative to the beginning of the file, os.SEEK_CUR or 1 to set it relative to the current position; os.SEEK_END or 2 to set it relative to the end of the file.
how − This is the reference point with-in the file. os.SEEK_SET or 0 means beginning of the file, os.SEEK_CUR or 1 means the current position and os.SEEK_END or 2 means end of the file.
This method does not return any value.
The following example shows the usage of lseek() method.
#!/usr/bin/python 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 you can use fsync() method. # Infact here you would not be able to see its effect. os.fsync(fd) # Now read this file from the beginning os.lseek(fd, 0, 0) str = os.read(fd, 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!!