Programming

hi,
i am trying to use popen to run a grep process and check if the pattern exists in the file that i am searching in. i am getting segmentation fault when i try to execute the following code

Code:

char *cd;
char flag[5];
char hdr_flpsp[4];
char hdr_flpsp2[4];
 FILE *fp;
printf ("program starts");
strcpy ( cd , "grep Pattern' /path/");
strcat ( cd ,"filename");
if ((fp = popen( cd, "r")) !=NULL)
{
strcpy ( hdr_flpsp, "ONE" );
strcpy (flag,"ONE");
printf ("value of flpsp_hdr flag is %\n", hdr_flpsp);
}
pclose (fp);

when i run this not even the intial printf message "program starts" is getting displayed. it straight aways throws segmentation fault error.
Can any one please tell me what wrong am i doing here?

You're trying to copy a "string" into unallocated memory (cd doesn't point anywhere yet). Also, for security reasons, it's better to use strncpy/strncat.