How to debug a C++ program that takes input from a script in gdb

Question

Background info: The C++ program(LAMMPS - an open source) takes in a input script that has all the commands to be executed. The executable is named "lmp_fedora", input script named "in.hit". The program's run command "./lmp_fedora < in.hit"

My Problem: I am trying to debug one of the .cpp files in LAMMPS.

My Attempts: 1. I tried "gdb lmp_fedora < in.hit", but it failed. 2. Also tried to find the pid of the running program using ps aux, but wasn't sure which id it was.

My Question: How do you debug a input script(that has commands linked to c++ project) using gdb?

Answer 1

You use the gdb run command:

$ gdb lmp_fedora
(gdb) run <in.hit

From the help:

(gdb) help run
Start debugged program.  You may specify arguments to give it.
Args may include "*", or "[...]"; they are expanded using "sh".
Input and output redirection with ">", "<", or ">>" are also allowed.

With no arguments, uses arguments last specified (with "run" or "set args").
To cancel previous arguments and run with no arguments,
use "set args" without arguments.

Answer 2

When you say gdb foo < bar that means bar is input to gdb , not to foo .

I think what you want to use is the gdb command set args .