POPEN(3) Library Functions Manual POPEN(3)NAME
popen, pclose - initiate I/O to/from a process
SYNOPSIS
#include <stdio.h>
FILE *popen(command, type)
char *command, *type;
pclose(stream)
FILE *stream;
DESCRIPTION
The arguments to popen are pointers to null-terminated strings containing respectively a shell command line and an I/O mode, either "r" for
reading or "w" for writing. It creates a pipe between the calling process and the command to be executed. The value returned is a stream
pointer that can be used (as appropriate) to write to the standard input of the command or read from its standard output.
A stream opened by popen should be closed by pclose, which waits for the associated process to terminate and returns the exit status of the
command.
Because open files are shared, a type "r" command may be used as an input filter, and a type "w" as an output filter.
SEE ALSO pipe(2), fopen(3S), fclose(3S), system(3), wait(2), sh(1)DIAGNOSTICS
Popen returns a null pointer if files or processes cannot be created, or the shell cannot be accessed.
Pclose returns -1 if stream is not associated with a `popened' command.
BUGS
Buffered reading before opening an input filter may leave the standard input of that filter mispositioned. Similar problems with an output
filter may be forestalled by careful buffer flushing, for instance, with fflush, see fclose(3S).
Popen always calls sh, never calls csh.
7th Edition May 15, 1985 POPEN(3)
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POPEN(3) Library Functions Manual POPEN(3)NAME
popen, pclose - initiate I/O to/from a process
SYNOPSIS
#include <stdio.h>
FILE *popen(const char *command, const char *type)
int pclose(FILE *stream)
DESCRIPTION
The arguments to popen are pointers to null-terminated strings containing respectively a shell command line and an I/O mode, either "r" for
reading or "w" for writing. It creates a pipe between the calling process and the command to be executed. The value returned is a stream
pointer that can be used (as appropriate) to write to the standard input of the command or read from its standard output.
A stream opened by popen should be closed by pclose, which waits for the associated process to terminate and returns the exit status of the
command.
Because open files are shared, a type "r" command may be used as an input filter, and a type "w" as an output filter.
SEE ALSO pipe(2), fopen(3), fclose(3), system(3), wait(2), sh(1).
DIAGNOSTICS
Popen returns a null pointer if files or processes cannot be created, or the shell cannot be accessed.
BUGS
Buffered reading before opening an input filter may leave the standard input of that filter mispositioned. Similar problems with an output
filter may be forestalled by careful buffer flushing, for instance, with fflush, see fclose(3).
7th Edition May 15, 1985 POPEN(3)
Hi all,
In my application i am trying to select some text & then give it to print. for this i am opening a stream using popen & then later closing using pclose.
Now this is working fine in my environment (solaris) but the pclose function is failing at my clients m/c. Even though print is... (3 Replies)
hello,
how can I filter and get the latest order number (last five digits) below:
input file:
johnmm00001
maryyy00121
johnm100222
johnmm00003
maryyy00122
output file:
johnmm00003
maryyy00122
johnm100222 (6 Replies)
Hi guys. Is it possible (I'm sure it is) to use the output of a simple 'ls' command as input of another command 'tail'.
It is not really the output of the 'ls'. I have to useeach line of the output.
This is the first command...
ls *myFile*021308*
Which it outputs many filenames. For each... (3 Replies)
Is there a way to tell for sure if a file currently is opened by any running process?
I have a task to filter a text file which is produced by some long process.
I have no way to communicate with that process, but I have access to a location, where that proces produce an output file.
Need... (3 Replies)
Hi,
The thing is that sometimes I need to filter an arbitrary output given a condition (think on the "filter" function present on some programming languages) from the shell (I use sh/bash). I tried this:
#!/bin/sh
# Usage: filter command
COMMAND=$1
shift 1
xargs "$@" -I "{}" sh -c "if... (3 Replies)
Hi,
I am trying to filter out those paragraphs that contains 'CONNECT', 'alter system switch logfile'. That means say the input file is :
-------------------------------------------------------
Wed Jun 7 00:32:31 2006
ACTION : 'CONNECT'
CLIENT USER: prdadm
CLIENT TERMINAL:
Wed Jun 7... (7 Replies)
Hi @all,
i really stuck in programming a tool with bidirectional process communication (popen(cmd, "rw") ... something like that ;-)).
Here is the code:
if(pipe(p_stdin) != 0 || pipe(p_stdout) != 0) {
fprintf(stderr, "Aufruf von pipe() schlug fehl.\n");
exit(1);
}
... (6 Replies)
Hi everyone,
Is there any way to use the pipe "|" operator to pass more than one input? For instance do:
(command1) (command2) | command3
with command 3 taking 2 parameters?
or maybe using ``s?
Thanks!
Anthony (4 Replies)
I am trying to create a csh clone, but am having problems implementing piped commands. Specifically, the below code simply hangs after input of ls | grep <text>
It does however filter the output and display it correctly, but it appears that grep hasn't exited and my shell never comes back to the... (16 Replies)
Hi
I want to filter my files which has more than 1 underscores in it.how can i achieve this.
Ex: if my file name is a_b_c, a_b.
my command should result only a_b_c
Thanks
Pracheth (10 Replies)
Hi,
Need some help with creating a file from input steam. Meaning from following command myfunc should be able to store the input stream to a file.
echo a b c | myfunc
The file thus created should have -
a
b
c
Here's what I've tried in myfunc() but didn't help -
myfunc() { cat... (3 Replies)
Hello all,
I am reading a huge zip file in POPEN process and then writting that to a normal file which of 2GB. Now the process is failing when I looked for the cause someother process comming in after I read my file and it is deleting the zip. But in theory the popen command should read the... (5 Replies)
Hi,
I have two files A and B and would like to use A as a filter. Like this:
File A.txt: Contains a list of IP addresses, each one occurring only once and in order:
10.0.0.1
10.0.0.2
10.0.0.4
10.0.0.8
File B.txt: Contains the same IP addresses with a corresponding ping time each (in... (16 Replies)