I am doing a project for the university and I have to do that a process has to create several children through fork(). The father process sends a pathname to each one through exec and the children must send to the father a list with the files from each directory.
The father is waiting and the children don't send anything. I must to do the pipe with mkfifo. I am trying to send text from the children but nothing happens. This is the code that I have wroten:
4. Complete Name of School (University), City (State), Country, Name of Professor, and Course Number (Link to Course):
University: Universidad de Castilla-La Mancha (Ciudad Real, spain)
Professor: Carlos Gonzalez Morcillo :: Personal Web Page www. inf-cr.uclm.es/www/cglez/ Degree: "Computer engineering" Subject: "Ampliación de Sistemas Operativos" + info: www. esi.uclm.es:8081/www/GuiaDocente/GuiaDocente0910/guias/42534_0910.pdf
In exec function say when i would like to remove the files
exec rm{}\;
Why is this "\" needed immediately after {} and what if i dont give it?
TIA,
Nisha (1 Reply)
Gurus,
I did my research (on google, this site and my local library) but I am *still* lost. I am trying to teach myself about `named pipes` playing around with MKFIFO (Why not?).
(1) It seems MKNOD is reserved to ROOT whereas MKFIFO is accessible to all users. Am I correct? If the answer is... (20 Replies)
I have read that exec "replaces the current process with a new one".
So I did
$ exec ls
and after this executed, my shell disappeared. I am assuming that my shell had PID xyz, and when I did exec ls, this ls got pid xyz, and when it terminated, there was no more shell process running, and... (5 Replies)
Hi all,
I had an issue regarding use of `` or exec in perl . `` are considered to be unsafe. Why? In my case an user would be giving some parameters as input and I will form an command of it and execute it using ``. It is important to capture output as i have to parse the output. As well as I need... (0 Replies)
Hello guys!
I am doing a project for the university and I have to do that a process has to create several children through fork(). The father process sends a pathname to each one through exec and the children must send to the father a list with the files from each directory.
The father is... (1 Reply)
Hi,
on AIX 6.L
I want to copy the result of grep -v to test directory then :
`hostname`@oracle$ls -l | grep -v RINT -exec cp {} test
grep: can't open -exec
grep: can't open cp
grep: can't open {}
test:°`.
Can you help me ?
Thank you. (3 Replies)
Hi,
I need to delete the last N days file using find.
I am trying to use
find . -mtime -10 -print
which lists down required files.
but when i use
find . -mtime -10 -exec ls -lrt {} \;
it gives me all files in the directory including the required files but the required files... (7 Replies)
I have the following bash script lines in a file named test.sh.
#!/bin/bash
#
# Write Date to cron.log
#
echo "Begin SSI Load $(date +%d%b%y_%T)"
#
# Get the latest rates file for processing.
#
d=$(ls -tr /rms/data/ssi | grep -v "processed" | tail -n 1)
filename=$d
export filename... (3 Replies)
Discussion started by: ginowms
3 Replies
LEARN ABOUT REDHAT
mkfifo
MKFIFO(3) Linux Programmer's Manual MKFIFO(3)NAME
mkfifo - make a FIFO special file (a named pipe)
SYNOPSIS
#include <sys/types.h>
#include <sys/stat.h>
int mkfifo(const char *pathname, mode_t mode);
DESCRIPTION
mkfifo makes a FIFO special file with name pathname. mode specifies the FIFO's permissions. It is modified by the process's umask in the
usual way: the permissions of the created file are (mode & ~umask).
A FIFO special file is similar to a pipe, except that it is created in a different way. Instead of being an anonymous communications chan-
nel, a FIFO special file is entered into the file system by calling mkfifo.
Once you have created a FIFO special file in this way, any process can open it for reading or writing, in the same way as an ordinary file.
However, it has to be open at both ends simultaneously before you can proceed to do any input or output operations on it. Opening a FIFO
for reading normally blocks until some other process opens the same FIFO for writing, and vice versa. See fifo(4) for non-blocking handling
of FIFO special files.
RETURN VALUE
The normal, successful return value from mkfifo is 0. In the case of an error, -1 is returned (in which case, errno is set appropriately).
ERRORS
EACCES One of the directories in pathname did not allow search (execute) permission.
EEXIST pathname already exists.
ENAMETOOLONG
Either the total length of pathname is greater than PATH_MAX, or an individual file name component has a length greater than
NAME_MAX. In the GNU system, there is no imposed limit on overall file name length, but some file systems may place limits on the
length of a component.
ENOENT A directory component in pathname does not exist or is a dangling symbolic link.
ENOSPC The directory or filesystem has no room for the new file.
ENOTDIR
A component used as a directory in pathname is not, in fact, a directory.
EROFS pathname refers to a read-only filesystem.
CONFORMING TO
POSIX.1
SEE ALSO mkfifo(1), read(2), write(2), open(2), close(2), stat(2), umask(2), fifo(4)Linux 1.2.13 1995-09-03 MKFIFO(3)