Section (1) tee
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
−p
-
diagnose errors writing to non pipes
−−output−error
[=MODE/]-
set behavior on write error. See MODE below
−−help
-
display this help and exit
−−version
-
output version information and exit
MODE determines behavior with write errors on the outputs:
- _zsingle_quotesz_warn_zsingle_quotesz_
-
diagnose errors writing to any output
- _zsingle_quotesz_warn−nopipe_zsingle_quotesz_
-
diagnose errors writing to any output not a pipe
- _zsingle_quotesz_exit_zsingle_quotesz_
-
exit on error writing to any output
- _zsingle_quotesz_exit−nopipe_zsingle_quotesz_
-
exit on error writing to any output not a pipe
The default MODE for the −p
option is _zsingle_quotesz_warn−nopipe_zsingle_quotesz_. The
default operation when −−output−error
is not
specified, is to exit immediately on error writing to a
pipe, and diagnose errors writing to non pipe outputs.
REPORTING BUGS
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Report any translation bugs to <https://translationproject.org/team/>
SEE ALSO
Full documentation <https://www.gnu.org/software/coreutils/tee>
or available locally via: info _zsingle_quotesz_(coreutils) tee invocation_zsingle_quotesz_
COPYRIGHT |
---|
Copyright © 2019 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>. This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. |
Section (2) tee
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 bit
mask that is composed by ORing together zero or more of the
following values:
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
- EAGAIN
-
SPLICE_F_NONBLOCK
was specified inflags
or one of the file descriptors had been marked as nonblocking (O_NONBLOCK
),
and the operation would block. - EINVAL
-
fd_in
orfd_out
does not refer to a pipe; orfd_in
andfd_out
refer to the same pipe. - ENOMEM
-
Out of memory.
VERSIONS
The tee
() system call first
appeared in Linux 2.6.17; library support was added to glibc
in version 2.5.
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 to the output by merely
grabbing a reference to the input.
EXAMPLE
The example below implements a basic tee(1) program using the
tee
() system call. Here is an
example of its use:
$ date |./a.out out.log | cat Tue Oct 28 10:06:00 CET 2014 $ cat out.log Tue Oct 28 10:06:00 CET 2014
Program source
#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); }
COLOPHON
This page is part of release 5.04 of the Linux man-pages
project. A
description of the project, information about reporting bugs,
and the latest version of this page, can be found at
https://www.kernel.org/doc/man−pages/.
This manpage is Copyright (C) 2006 Jens Axboe and Copyright (C) 2006 Michael Kerrisk <mtk.manpagesgmail.com> %%%LICENSE_START(VERBATIM) Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Since the Linux kernel and libraries are constantly changing, this manual page may be incorrect or out-of-date. The author(s) assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. The author(s) may not have taken the same level of care in the production of this manual, which is licensed free of charge, as they might when working professionally. Formatted or processed versions of this manual, if unaccompanied by the source, must acknowledge the copyright and authors of this work. %%%LICENSE_END |