Search results
Results from the WOW.Com Content Network
The reason for this is to distinguish between a file named '1' and stdout, i.e. cat file 2 >1 vs cat file 2 > & 1. In the first case, stderr is redirected to a file named ' 1 ' and in the second, stderr is redirected to stdout. Another useful capability is to redirect one standard file handle to another.
>> file means stdout will be appended at the end of file. >>& file means both stdout and stderr will be appended at the end of file. < file means stdin will be read from file. << string is a here document. Stdin will read the following lines up to the one that matches string. Redirecting stderr alone isn't possible without the aid of a sub-shell.
The C programming language provides many standard library functions for file input and output.These functions make up the bulk of the C standard library header <stdio.h>. [1] The functionality descends from a "portable I/O package" written by Mike Lesk at Bell Labs in the early 1970s, [2] and officially became part of the Unix operating system in Version 7.
In the case of an interactive shell, that is usually the text terminal which initiated the program. The file descriptor for standard output is 1 (one); the POSIX <unistd.h> definition is STDOUT_FILENO; the corresponding C <stdio.h> variable is FILE* stdout; similarly, the C++ <iostream> variable is std::cout.
If a file named program.lint already exists, it is deleted and replaced. Similarly, both the stdout and stderr output streams can be redirected to standard output and the program.lint using stream redirection:
Yes (stdin, stdout, stderr, stdout+stderr) Yes (via registry, TCMD.INI / 4NT.INI file, startup parameters, environment variables, SETDOS command) Yes (automatic via registry and TCSTART / 4START as well as TCEXIT / 4EXIT, or explicitly via /K startup option) Yes (via CALL command or /C and /K startup options) Yes No VMS DCL [22] OpenVMS
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
Under Unix, devices are files too, so the normal type of file for the shell used for stdin, stdout and stderr is a tty device file. Another command-line interface allows a shell program to launch helper programs, either to launch documents or start a program.