topic running shell scrit form C++ in Operating System - Linux

running shell scrit form C++

msbinu — Fri, 19 May 2006 11:34:46 GMT

Hi ,

I have to run a shell scipt form my C++ file and get the output obtained by running the script in my cpp file.
Can any one throw some light as to how to do this

Thanks in advance
regards
Binu

Re: running shell scrit form C++

Arunvijai_4 — Fri, 19 May 2006 11:46:56 GMT

Hi Binu,

Have you tried using "system()" call ? I think, it should be helpful to you

-Arun

Re: running shell scrit form C++

A. Clay Stephenson — Fri, 19 May 2006 12:29:20 GMT

The system() function is not a wise choice as the only thing returned is the exit status of the command. You really want to open a pipe for reading via popen() to capture the output of a shell script. pclose() will return the exit status of the command. Man popen, pclose for details.

Re: running shell scrit form C++

Bill Hassell — Fri, 19 May 2006 12:57:51 GMT

And make sure that *all* of your scripts have the interpreter listed in line 1. Scripts will run without this line but only under specific circumstances. The line looks like this:

#!/usr/bin/sh

(or ksh or csh or perl....whatever)
Without that line, there is no way to know how to run the script (scripts always require an interpreter, typically a shell or scripting language amd the C program is not a shell)

Re: running shell scrit form C++

Sung Oh — Fri, 19 May 2006 13:38:12 GMT

hi Binu,

You can use "sprintf" function

eg.
(void)sprintf(cmd, "cat /proc/iomem 2>/dev/null", idedb[i].device);

and you can use "popen" function

if ((fp = (FILE *)popen("cat /proc/iomem 2>/dev/null", "r")) == NULL) {
error ("popen failed when trying to view iomem data");
return (1);
}

http://www.phim.unibe.ch/comp_doc/c_manual/C/FUNCTIONS/popen.html

Regards,
Sung

Re: running shell scrit form C++

A. Clay Stephenson — Fri, 19 May 2006 22:04:47 GMT

WRONG:
(void)sprintf(cmd, "cat /proc/iomem 2>/dev/null", idedb[i].device);

The sprintf command by itself will do nothing except build the string "cmd" that might later be used in a system(cmd) function or a popen(cmd,"r").

Re: running shell scrit form C++

msbinu — Thu, 25 May 2006 08:54:12 GMT

Thanks all for your help