Is a file descriptor a socket?

Is a file descriptor a socket?

There is no difference between socket (descriptor) and file descriptor(s). Socket is just special form of file. For example, you can use same syscalls read() and write() on socket descriptors that are used on file descriptors.

What is use of lsof command?

lsof command stands for List Of Open File. This command provides a list of files that are opened. Basically, it gives the information to find out the files which are opened by which process. With one go it lists out all open files in output console.

What is file descriptor Linux?

In Unix and Unix-like computer operating systems, a file descriptor (FD, less frequently fildes) is a unique identifier (handle) for a file or other input/output resource, such as a pipe or network socket.

Where does the file name go in a listening socket?

The name of such a file is linked into the /proc/ /fd/ directory using the process specific value of the file descriptor for this socket. All other sockets do not have a representation in the file system. Are these UNIX listening sockets?

Where is the file associated with AF _ UNIX typed sockets?

Only named UNIX Domain Name sockets ( AF_UNIX typed sockets) have a file associated. The name of such a file is linked into the /proc/ /fd/ directory using the process specific value of the file descriptor for this socket. All other sockets do not have a representation in the file system.

Does a program take file descriptor 0 1 2 for stdin?

When a program begins, does it take file descriptor 0 1 2 for stdin, stdout and stderr by default . If you launch your program in an interactive shell normally, yes.

When does a program begin, does it take file descriptor 0?

When a program begins, does it take file descriptor 0 1 2 for stdin, stdout and stderr by default . If you launch your program in an interactive shell normally, yes. Inheriting a socket as FD 0 also happens if the program is started by inetd, or anything else that behaves the same way.