The && will cause the shell to wait before running the command after it, and should any of them fail, none of the ones after it will run. && is a conditional, it's not a background statement. Also, is there any particular reason that string of commands is all in one line? And what is 'echo exec' for, did you mean for that to be without the echo?
I don't think there's any point trying to open it as a FD in the shell if you're trying to save time, since the shell will wait for the reader to open the pipe anyway. Once it does, all three processes will get the same pipe, which I doubt is what you want. at which point all three processes will get copies of the same pipe, not queue up.
This sort of code, on the other hand, will wait for the pipe, launch a process, then immediately wait on the pipe again without waiting for the launched process to finish:
I'm in highschool. They blocked my favorite site. How do I disable websense without getting caught on that particular webpage? Is it even possible? *twitch* I would also like to get as much UNIX for beginners information, so if someone might point me in the right direction so I don't have to read... (1 Reply)
I've got a legit DHCP server on my network. I've got a 3550 as my VTP server providing 4 vlans to 4 2950 switches. If somebody were to plug into one of those vlans with a DHCP server configured then it would throw off my whole network. How could i block the DHCP server that could plug into the... (2 Replies)
Hi!!
I have a problem reading from a fifo pipe in shell script.
The idea is simple, I have a C program with two pipe files:
An input pipe I use to send commands in shell script to the C program (echo "command" > input.pipe)
An output pipe that I read the result of the command also in... (4 Replies)
Hi Folks
I have been debugging a script that is called every thirty seconds. Basically it is doing a ps, well two actually, one to file (read by the getline below) and the other into a pipe. The one into the pipe is: -
V_SYSVPS=/usr/sysv/bin/ps
$V_SYSVPS -p$PIDLIST -o$PSARGS... (0 Replies)
I know how to add signal to a set. But what if I want to add 2 or 3 signals to the set.
I know I can use sigaddset (&set,SIGBUS)....but what if I want to add SIGBUS and SIGALRM at once. Do i have to do it like this..
sigaddset (&set,SIGBUS);
sigaddset (&set,SIGALRM);
Is there another way to... (0 Replies)
Hi
I am starting to practice nmap for my own education.
Now I created two host in virtual box.
Bot are scientific linux, one in installed as web server and the other as developing station.
I tried to run nmap on so I did nmap on their IP address, I got an answer that ip is down or that... (8 Replies)
Hi guys,
I need to know how i can ignore Pipe '|' if Pipe is coming as a column in Pipe delimited file
for eg:
file 1:
xx|yy|"xyz|zzz"|zzz|12...
using below awk command
awk 'BEGIN {FS=OFS="|" } print $3
i would get xyz
But i want as :
xyz|zzz to consider as whole column... (13 Replies)
among the below socket programming api's, please let me know which are blocking and non-blocking.
socket
accept
bind
listen
write
read
close (2 Replies)
Discussion started by: VSSajjan
2 Replies
LEARN ABOUT LINUX
connld
connld(7M) STREAMS Modules connld(7M)NAME
connld - line discipline for unique stream connections
SYNOPSIS
#include </sys/steam.h>
int ioctl(fd,I_PUSH,"connld");
DESCRIPTION
connld is a STREAMS-based module that provides unique connections between server and client processes. It can only be pushed (see
streamio(7I)) onto one end of a STREAMS-based
pipe that may subsequently be attached to a name in the file system name space with fattach(3C). After the pipe end is attached, a new
pipe is created internally when an originating process attempts to open(2) or creat(2) the file system name. A file descriptor for one
end of the new pipe is packaged into a message identical to that for the ioctl I_SENDFD (see streamio(7I)) and is transmitted along the
stream to the server process on the other end. The originating process is blocked until the server responds.
The server responds to the I_SENDFD request by accepting the file descriptor through the I_RECVFD ioctl message. When this happens, the
file descriptor associated with the other end of the new pipe is transmitted to the originating process as the file descriptor returned
from open(2) or creat(2).
If the server does not respond to the I_SENDFD request, the stream that the connld module is pushed on becomes uni-directional because the
server will not be able to retrieve any data off the stream until the I_RECVFD request is issued. If the server process exits before
issuing the I_RECVFD request, the open(2) or the creat(2) invocation will fail and return -1 to the originating process.
When the connld module is pushed onto a pipe, it ignores messages going back and forth through the pipe.
ERRORS
On success, an open of connld returns 0. On failure, errno is set to the following values:
EINVAL A stream onto which connld is being pushed is not a pipe or the pipe does not have a write queue pointer pointing to a
stream head read queue.
EINVAL The other end of the pipe onto which connld is being pushed is linked under a multiplexor.
EPIPE connld is being pushed onto a pipe end whose other end is no longer there.
ENOMEM An internal pipe could not be created.
ENXIO An M_HANGUP message is at the stream head of the pipe onto which connld is being pushed.
EAGAIN Internal data structures could not be allocated.
ENFILE A file table entry could not be allocated.
SEE ALSO creat(2), open(2), fattach(3C), streamio(7I)
STREAMS Programming Guide
SunOS 5.10 3 May 2004 connld(7M)