[LLDB] lldb-mi debugger not able to take input file as an exe argument

Hi, I am trying to debug a program which takes a input file. It works in command line when I run it as ./a.out <testinput.txt and when I try to debug it I get the following output and debugger hangs as if it doesnot get any input.

Launching: '/Users/wge/Github/CSE340cpp/Pj3/a.out'
Working directory: '/Users/wge/Github/CSE340cpp/Pj3'
2 arguments:
argv[0] = '/Users/wge/Github/CSE340cpp/Pj3/a.out'
argv[1] = '<testa8t.txt'

I did try put < and testfile.txt in two arguments with no difference.
I set the external console to be true but it doesn't seem like there is a way for cpp debugger to accept a input like regular command line would?
I am using vscode 1.17 and lastest cpp extension with lldb on Mac OSX.

{
"version": "0.2.0",
"configurations": [
{
"name": "(lldb) Launch",
"type": "cppdbg",
"request": "launch",
"program": "${workspaceRoot}/a.out",
"args": ["<testa8t.txt"],
"stopAtEntry": false,
"cwd": "${workspaceRoot}",
"environment": [],
"externalConsole": true,
"osx": {
"MIMode": "lldb"
}
}
]
}

Start by reproducing the reported launch.json configuration on macOS with LLDB, focusing on the args and externalConsole settings. Confirm whether stdin redirection from the input file is delivered to the debugged program; done means the program accepts the file input while launched through the C/C++ debugger.