How do I run a program with commandline arguments using GDB within a Bash script?

You can run gdb with --args parameter:

gdb --args executablename arg1 arg2 arg3

If you are doing this often (e.g. when running GDB from a script), you might want to consider the following arguments to automate things further. First, you can place your GDB commands (such as 'run') in a text file and provide the filename to the -x argument. Second, you can have GDB exit after running your commands by providing the --batch argument. A full example:

gdb -x commands.txt --batch --args executablename arg1 arg2 arg3

gdb -ex=r --args myprogram arg1 arg2

-ex=r is short for -ex=run and tells gdb to run your program immediately, rather than wait for you to type "run" at the prompt. Then --args says that everything that follows is the command and arguments, just as you'd normally type them at the commandline prompt.