I'm not sure I'm following what is going on here, but I think you want something more like:
This assumes that yuv4mpeg_to_v4l2 is reading data from standard input and feeding it into your display device while mplayer is converting tom_and_jerry.mp4 into a format that yuv4mpeg_to_v4l2 reads and directs its output to the file named by the -vo yuv4mpeg:file=pathname option's option argument.
It also assumes that mplayer does not write anything to its standard output (and that nothing else inside the while loop writes anything to standard output). The FIFO has to be kept open by something on both the read end (which is being done by yuv4mpeg_to_v4l2) and on the write end (which I am doing with the redirection on the while loop). If mplayer is the only thing writing to the FIFO, the write end will close after mplayer finishes the conversion once and yuv4mpeg_to_v4l2 will see an EOF.
Hi everybody, first of all i am a new member in UNIX.com and this is my first post.
I am impressed with the amount of information a person can ever have in this forum, it is really great having something similiar; anyways let me tell you about the problem I am having, hope you will answer me.... (6 Replies)
Hi,
in my script I need to execute the following command:
query $id 456 432
but it waits for a RETURN character from keyboard and therefore, it fails. I tried something like:
query $id 456 432 << '\n'
but, i'ts clear it is not correct. Is there any way to do this?
Thxs. (0 Replies)
while running a user inter-active program
how can we get the commands from a
file instead of the user?
is there anyway to permanently redirect content
of a file to standard input? (6 Replies)
Hello,
I need to change user and run some commands by using a script.
lets say, I'm using
su - someuser << start
password required -----> how can I enter the password here
command 1
command 2
command 3
command 4
start
While trying to run this I got the following message:
"standard... (2 Replies)
Hello,
I need help with a bash script that I try to improve. I could not find answer so far, maybe because I'm not to familiar with the terminology so feel free to correct my language.
I have a script that looks like:
NODES="node_a node_b node_c"
for NODE in $NODES
do
... (4 Replies)
All,
I have a requirement to write a script where I check for Input redirection when the script was executed, based on which I handle my logic. Below is the example:
my.script
#! /bin/ksh
# Not sure how to frame the if condition below
if ; then
echo "Input Redirected from a file"
... (7 Replies)
Hello everyone,
My requirement is that within a script I need to construct the command line exactly that it was invoked with. For example :
sh a.sh arg1 arg2 arg3 < input.txt > output.txt
Now within a.sh, I construct a file which has these contents "
sh a.sh arg1 arg2 arg3 < input.txt >... (8 Replies)
Can someone please explain when input redirection is necessary?
For example, "cat filename" and "cat< filename" produce the same result. I was told that if I need to bunzip a file that I should type "bunzip2<filename.bz2." However, if I omit the "<" I still get the same result. Can someone... (4 Replies)
Hi,
when I try to redirect input and the command is described as a string within an array redirection does not work. why?
#!/bin/bash
dir=("tail < ./hello.txt")
tail < ./hello.txt #works
${dir} #does not work (2 Replies)
Discussion started by: heinzel
2 Replies
LEARN ABOUT DEBIAN
explain_pipe_or_die
explain_pipe_or_die(3) Library Functions Manual explain_pipe_or_die(3)NAME
explain_pipe_or_die - create pipe and report errors
SYNOPSIS
#include <libexplain/pipe.h>
void explain_pipe_or_die(int *pipefd);
DESCRIPTION
The explain_pipe_or_die function is used to call the pipe(2) system call. On failure an explanation will be printed to stderr, obtained
from explain_pipe(3), and then the process terminates by calling exit(EXIT_FAILURE).
This function is intended to be used in a fashion similar to the following example:
explain_pipe_or_die(pipefd);
pipefd The pipefd, exactly as to be passed to the pipe(2) system call.
Returns:
This function only returns on success. On failure, prints an explanation and exits.
SEE ALSO pipe(2) create pipe
explain_pipe(3)
explain pipe(2) errors
exit(2) terminate the calling process
COPYRIGHT
libexplain version 0.52
Copyright (C) 2009 Peter Miller
explain_pipe_or_die(3)