DZone Snippets: program code

Simple way to check command line arguments in a C program

jmftrindade (Joana M. F. da Trindade) — Mon, 25 Feb 2008 22:49:18 GMT

A simple way to check command line arguments.

Author: Joana Matos Fonseca da Trindade
Date: 2008.02.25



#include 

#include 

#include 



/* minimum required number of parameters */

#define MIN_REQUIRED 2



/* display usage */

int help() {

   printf("Usage: myprogram [-s ] [-n ] [-true]\n");

   printf("\t-s: a string a\n");

   printf("\t-n: a number\n");

   printf("\t-true: a single parameter\n");



   return 1;

}



/* main */

int main(int argc, char *argv[]) {

   if (argc < MIN_REQUIRED) {

      return help();

   }

   int i;



   /* iterate over all arguments */

   for (i = 1; i < (argc - 1); i++) {

       if (strcmp("-s", argv[i]) == 0) {

          /* do something with it */ 

          printf("string = %s\n", argv[++i]);

          continue;

       }

       if (strcmp("-n", argv[i]) == 0) {

          /* do something with it. for example, convert it to an integer */

          printf("number = %i\n", atoi(argv[++i]));

          continue;

       }

       if (strcmp("-true", argv[i]) == 0) {

          printf("true activated\n");

          continue;

       }

       return help();

   }

   return 0;

}

Making SQLITE/SQLITE3 executable scripts.

ttmrichter (Michael T. Richter) — Mon, 04 Dec 2006 18:54:28 GMT

Use "here document" statements to build complex script files with embedded SQL statements via the sqlite/sqlite3 utility.



#! /usr/bin/env bash



# execute some bash scripting commands here



sqlite3 mydatabase <SELECT * 

  FROM mytable 

  WHERE somecondition='somevalue';

SQL_ENTRY_TAG_1



# execute other bash scripting commands here



sqlite3 mydatabase <SELECT *

  FROM myothertable

  WHERE someothercondition='someothervalue';

SQL_ENTRY_TAG_2

Note that being in a bash script means that you can expand $-variables inside the SQL code directly. This is, however, not advised unless you can be sure that only trusted, competent people will run your code. Otherwise you'll be facing SQL injection attacks.

Making MySQL executable scripts.

ttmrichter (Michael T. Richter) — Mon, 04 Dec 2006 18:34:52 GMT

Use "here document" statements to build complex script files with embedded SQL statements via the mysql utility.



#! /usr/bin/env bash



# execute some bash scripting commands here



mysql mydatabase <SELECT * 

  FROM mytable 

  WHERE somecondition='somevalue';

SQL_ENTRY_TAG_1



# execute other bash scripting commands here



mysql mydatabase <SELECT *

  FROM myothertable

  WHERE someothercondition='someothervalue';

SQL_ENTRY_TAG_2