getopt

getopt(int argc, char * const argv[], const char *optstring)

get option character from command line argument list

ex:getopt(argc, argv, “bf:")

     options are b & f

strdup

char *  strdup(const char *s1); 

allocates sufficient memory for a copy of the string s1, 

does the copy, and returns a pointer to it.

strstr

strstr(const char *s1, const char *s2);

locate a substring in a string