This is weird, so I'm hoping someone here knows solaris and how it handles pipes...
OK... here goes...
Theres this log file, right? I want to tail -f it, grep that, gzip that, then pipe that into more commands. Well thats easy, right?
tail -f file | grep pattern | gzip | otherstuff...
... (1 Reply)
Hi,
Can the cd command be invoked using pipes???
My actual question is slightly different. I am trying to run an executable from different folders and the path of these folders are obtained dynamically from the front end. Is there a way in which i can actually run the executable... (2 Replies)
I am trying to figure out why when i have the following code
int main( { printf("0\n"); fork(); printf("1\n"); exit(0);}
and type in the shell
a.out | cat
the output of this program is
0
1
0
1
instead of
0
1
1
does anyone know? (3 Replies)
This is something I've given a lot of thought to and come up with no answer.
Say you have a data stream passing from a file, through process A, into process B. Process A only modifies a few bytes of the stream, then prints the rest of the stream unmodified. Is there any way to stream the file... (4 Replies)
Hi,
thanks for b4. can anyone tell me why following not working:
noUsers=$(who | cut -d" " -f1 | wc -l)
What i'm trying to do is get a list of logged on users and pass it to 'wc -l' and store the output to a variable. Any ideas? (1 Reply)
Hello all, I am trying to learn more about programming Unix pipes in C.
I have created a pipe that does od -bc < myfile | head
Now, I am trying to create od -bc < myfile | head | wc
Here is my code, and I know I might be off, thats why I am here so I can get some clarification.
#include... (1 Reply)
ls --color=always -laX | awk '{print $1, $3, $4, $2, $8}'
|sort -k 1,1 -k 9,9r
they work separately... but i don't know how to combine this to work.
thx! (1 Reply)
Hi, I have two programs, one is named "Master" and the other one "slave". What I want to do is , when I execute Master, inside slave will be called by excecl, do some calculations, and send those to the master program... A little example of what I am failing to do:
if ((PID1=fork())==0) { //... (6 Replies)
Discussion started by: lamachejo
6 Replies
LEARN ABOUT MINIX
fork
FORK(2) System Calls Manual FORK(2)NAME
fork - create a new process
SYNOPSIS
#include <sys/types.h>
#include <unistd.h>
pid_t fork(void)
DESCRIPTION
Fork causes creation of a new process. The new process (child process) is an exact copy of the calling process except for the following:
The child process has a unique process ID.
The child process has a different parent process ID (i.e., the process ID of the parent process).
The child process has its own copy of the parent's descriptors. These descriptors reference the same underlying objects, so that,
for instance, file pointers in file objects are shared between the child and the parent, so that an lseek(2) on a descriptor in the
child process can affect a subsequent read or write by the parent. This descriptor copying is also used by the shell to establish
standard input and output for newly created processes as well as to set up pipes.
The child starts with no pending signals and an inactive alarm timer.
RETURN VALUE
Upon successful completion, fork returns a value of 0 to the child process and returns the process ID of the child process to the parent
process. Otherwise, a value of -1 is returned to the parent process, no child process is created, and the global variable errno is set to
indicate the error.
ERRORS
Fork will fail and no child process will be created if one or more of the following are true:
[EAGAIN] The system-imposed limit on the total number of processes under execution would be exceeded. This limit is configuration-
dependent. (The kernel variable NR_PROCS in <minix/config.h> (Minix), or <minix/const.h> (Minix-vmd).)
[ENOMEM] There is insufficient (virtual) memory for the new process.
SEE ALSO execve(2), wait(2).
3rd Berkeley Distribution May 22, 1986 FORK(2)