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tee

read from standard input and write to standard output and files


  1. tee.1.man
  2. tee.2.man


1. tee.1.man

Manpage of TEE

TEE

Section: User Commands (1)
Updated: October 2011
Index Return to Main Contents
 

NAME

tee - read from standard input and write to standard output and files  

SYNOPSIS

tee [OPTION]... [FILE]...  

DESCRIPTION

Copy standard input to each FILE, and also to standard output.

-a, --append
append to the given FILEs, do not overwrite
-i, --ignore-interrupts
ignore interrupt signals
--help
display this help and exit
--version
output version information and exit

If a FILE is -, copy again to standard output.  

AUTHOR

Written by Mike Parker, Richard M. Stallman, and David MacKenzie.  

REPORTING BUGS

Report tee bugs to bug-coreutils@gnu.org
GNU coreutils home page: <http://www.gnu.org/software/coreutils/>
General help using GNU software: <http://www.gnu.org/gethelp/>
Report tee translation bugs to <http://translationproject.org/team/>  

COPYRIGHT

Copyright © 2011 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl>.
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.  

SEE ALSO

The full documentation for tee is maintained as a Texinfo manual. If the info and tee programs are properly installed at your site, the command
info coreutils aqtee invocationaq

should give you access to the complete manual.


 

Index

NAME
SYNOPSIS
DESCRIPTION
AUTHOR
REPORTING BUGS
COPYRIGHT
SEE ALSO

This document was created by man2html using the manual pages.
Time: 17:32:45 GMT, October 23, 2013

2. tee.2.man

Manpage of TEE

TEE

Section: Linux Programmer's Manual (2)
Updated: 2009-09-15
Index Return to Main Contents
 

NAME

tee - duplicating pipe content  

SYNOPSIS

#define _GNU_SOURCE         /* See feature_test_macros(7) */
#include <fcntl.h>

ssize_t tee(int fd_in, int fd_out, size_t len, unsigned int flags);
 

DESCRIPTION

tee() duplicates up to len bytes of data from the pipe referred to by the file descriptor fd_in to the pipe referred to by the file descriptor fd_out. It does not consume the data that is duplicated from fd_in; therefore, that data can be copied by a subsequent splice(2).

flags is a series of modifier flags, which share the name space with splice(2) and vmsplice(2):

SPLICE_F_MOVE
Currently has no effect for tee(); see splice(2).
SPLICE_F_NONBLOCK
Do not block on I/O; see splice(2) for further details.
SPLICE_F_MORE
Currently has no effect for tee(), but may be implemented in the future; see splice(2).
SPLICE_F_GIFT
Unused for tee(); see vmsplice(2).
 

RETURN VALUE

Upon successful completion, tee() returns the number of bytes that were duplicated between the input and output. A return value of 0 means that there was no data to transfer, and it would not make sense to block, because there are no writers connected to the write end of the pipe referred to by fd_in.

On error, tee() returns -1 and errno is set to indicate the error.  

ERRORS

EINVAL
fd_in or fd_out does not refer to a pipe; or fd_in and fd_out refer to the same pipe.
ENOMEM
Out of memory.
 

VERSIONS

The tee() system call first appeared in Linux 2.6.17.  

CONFORMING TO

This system call is Linux-specific.  

NOTES

Conceptually, tee() copies the data between the two pipes. In reality no real data copying takes place though: under the covers, tee() assigns data in the output by merely grabbing a reference to the input.  

EXAMPLE

The following example implements a basic tee(1) program using the tee() system call.

#define _GNU_SOURCE
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <limits.h>

int
main(int argc, char *argv[])
{
    int fd;
    int len, slen;

    if (argc != 2) {
        fprintf(stderr, "Usage: %s <file>
", argv[0]); exit(EXIT_FAILURE); } fd = open(argv[1], O_WRONLY | O_CREAT | O_TRUNC, 0644); if (fd == -1) { perror("open"); exit(EXIT_FAILURE); } do { /* * tee stdin to stdout. */ len = tee(STDIN_FILENO, STDOUT_FILENO, INT_MAX, SPLICE_F_NONBLOCK); if (len < 0) { if (errno == EAGAIN) continue; perror("tee"); exit(EXIT_FAILURE); } else if (len == 0) break; /* * Consume stdin by splicing it to a file. */ while (len > 0) { slen = splice(STDIN_FILENO, NULL, fd, NULL, len, SPLICE_F_MOVE); if (slen < 0) { perror("splice"); break; } len -= slen; } } while (1); close(fd); exit(EXIT_SUCCESS); }
 

SEE ALSO

splice(2), vmsplice(2)  

COLOPHON

This page is part of release 3.32 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.


 

Index

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
VERSIONS
CONFORMING TO
NOTES
EXAMPLE
SEE ALSO
COLOPHON

This document was created by man2html using the manual pages.
Time: 17:32:45 GMT, October 23, 2013

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