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An important aspect of this, setting Unix pipes apart from other pipe implementations, is the concept of buffering: for example a sending program may produce 5000 bytes per second, and a receiving program may only be able to accept 100 bytes per second, but no data is lost. Instead, the output of the sending program is held in the buffer.
In computing, redirection is a form of interprocess communication, and is a function common to most command-line interpreters, including the various Unix shells that can redirect standard streams to user-specified locations. The concept of redirection is quite old, dating back to the earliest operating systems (OS).
Unix shells use dup2 for input/output redirection. Along with pipe() , it is a tool on which Unix pipes rely. The following example uses pipe() and dup() in order to connect two separate processes ( program1 and program2 ) using Unix pipes :
Anonymous pipe: A unidirectional data channel using standard input and output. Data written to the write-end of the pipe is buffered by the operating system until it is read from the read-end of the pipe. Two-way communication between processes can be achieved by using two pipes in opposite "directions". All POSIX systems, Windows Named pipe
On Microsoft Windows, reads and writes to anonymous pipes are always blocking. [1] In other words, a read from an empty pipe will cause the calling thread to wait until at least one byte becomes available or an end-of-file is received as a result of the write handle of the pipe being closed. Likewise, a write to a full pipe will cause the ...
Process substitution can also be used to capture output that would normally go to a file, and redirect it to the input of a process. The Bash syntax for writing to a process is >(command) . Here is an example using the tee , wc and gzip commands that counts the lines in a file with wc -l and compresses it with gzip in one pass:
Every pipe is placed in the root directory of the named pipe filesystem (NPFS), mounted under the special path \\.\pipe\ (that is, a pipe named "foo" would have a full path name of \\.\pipe\foo). Anonymous pipes used in pipelining are actually named pipes with a random name. They are very rarely seen by users, but there are notable exceptions.
After instantiating a new socket, the server binds the socket to an address. For a Unix domain socket, the address is a /path/filename.. Because the socket address may be either a /path/filename or an IP_address:Port_number, the socket application programming interface requires the address to first be set into a structure.