system, exec, shell_exec, passthru

Hello, I am trying the run an external application with command line arguments using PHP under linux. ie: $command="myprog $arg1 $arg2 > textfile.txt"; system("echo \"$command\" > test.txt"); system($command); $handle=fopen("textfile.txt","r"); if($handle!=NULL) { while(!feof($handle)) { ... } fclose($handle); } I test my input arguments for the 'system' call by dumping the command into a text file. I can then test the command in the console. The commands work fine when run from the console. The commands don't work when run through the system command. I have tried system, exec, passthru, and shell_exec to no avail. Am I missing some permissions thing in my php.ini file? Thanks for any insight, Peter