and
produce the same output*, but this is not the case for printf
This is why you got the output, since unquoted it produces multiple lines and read LEFT CENTER RIGHT only reads the first line..
--
* In the first case there are 3 arguments, in the second case there is only one.
--
"%q" is likely not portable.
Also I don't expect it to work as intended, try putting quotes around the output of the variables:
Then printf "%q\n" "This is piped" | printe - produces:
Last edited by Scrutinizer; 03-13-2020 at 02:57 AM..
i made a lot of processes. here is the code:
main()
{
printf("\nEnter K="); scanf("%d",&k);
printf("Enter L="); scanf("%d",&l);
printf("\nFather id=%d\n",getpid());
x=0;
makechild();
sleep(2);
return 1;
}
int makechild()
{
for(q=1;q<=k;q++)
{
if(f=fork())
{
... (5 Replies)
Hi,
I have a shell scripting. This will take 7 digit number in each line and add 7 digit number with next subsequent lines ( normal addition ).
Eg:
0000001
0000220
0001235
0000022
0000023
...........
.........
........
Like this i am having around 1500000 records. After adding... (23 Replies)
Hi I have a problem writing a c program that makes a telnet connection and writes some command.
The shell command is something like this:
------------------------------------------------------------------
>
>telnet 141.111.231.132 3300
ENTER COMMAND: login "<--- I' wirte a command (ex... (5 Replies)
Hi, guys:
I am working on my shell using c. How can I use pipe to implement the following?
ls -l 1>> | grep hellp 1<< 2>> | less 2<<
(the output of ls goes to grep, and the output of grep goes to less)
Thanks
Please use and tags when posting code, data or logs etc. to preserve... (1 Reply)
Hello everyone, I'm in need of some assistance. I'm currently enrolled in an introductory UNIX shell programming course and, well halfway through the semester, we are receiving our first actual assignment. I've somewhat realized now that I've fallen behind, and I'm working to get caught up, but for... (1 Reply)
Hi All,
I am using the below script which has awk command, but it is not returing the expected result. can some pls help me to correct the command.
The below script sample.ksh should give the result if the value of last 4 digits in the variable NM matches with the variable value DAT. The... (7 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)
Hello,
I have an ffmpeg bash script which is working nice and
I need to do the same for other sources.
To create new scripts and to deal with multiple bash files sounds not logical. It is a bit hard to manage for me..
I wondered if it was possible to make my input file as variable.
Then I... (1 Reply)
Discussion started by: baris35
1 Replies
LEARN ABOUT ULTRIX
pipe
pipe(2) System Calls Manual pipe(2)Name
pipe - create an interprocess channel
Syntax
include <limits.h> /*Definition of PIPE_MAX*/
pipe(fildes)
int fildes[2];
Arguments
fildes Passing an address as an array of two integers into the system call.
Description
The system call creates an I/O mechanism called a pipe. The file descriptors returned can be used in and operations. Their integer values
will be the two lowest available at the time of the function call. The O_NONBLOCK and FD_CLOEXEC flags will be clear on both file descrip-
tors.
When the pipe is written using the descriptor fildes[1], up to PIPE_MAX bytes of data are buffered before the writing process is suspended.
A read using the descriptor fildes[0] picks up the data.
It is assumed that after the pipe has been set up, two (or more) cooperating processes (created by subsequent calls) pass data through the
pipe with and calls.
The shell has a syntax to set up a linear array of processes connected by pipes.
For further information on how and calls behave with pipes, see the and reference pages.
A signal is generated if a write on a pipe with only one end is attempted.
Restrictions
Should more than 4096 bytes be necessary in any pipe among a loop of processes, deadlock may occur.
The underlying implementation of pipes is no longer socket based, but rather implemented through the file system. Any application that
needs socket functionality from pipes should use the system call.
Return Values
The function value zero is returned if the pipe was created; -1 if an error occurred.
Diagnostics
The call fails if:
[EMFILE] Too many descriptors are active.
[ENFILE] The system file table is full.
[EFAULT] The fildes buffer is in an invalid area of the process's address space.
Environment
Differs from the System V definition in that ENFILE is not a possible error condition.
See Alsosh(1), fork(2), read(2), socketpair(2), write(2)pipe(2)