Implement --pdb in a python cli
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Adding a flag to your applications can make them much easier for those using it to debug your application, especially if your applicatoin is a cli...

Date: January 13, 2022

Adding a --pdb flag to your applications can make them much easier for those using it to debug your application, especially if your applicatoin is a cli application where the user has much fewer options to start this for themselves. To add a pdb flag --pdb to your applications you will need to wrap your function call in a try/except, and start a post_mortem debugger. I give credit to this stack overflow post <https://stackoverflow.com/questions/242485/starting-python-debugger-automatically-on-error> for helping me figure this out.

```
import pdb, traceback, sys


def bombs():
    a = []
    print(a[0])


if __name__ == "__main__":
    if "--pdb" in sys.argv:
        try:
            bombs()
        except:
            extype, value, tb = sys.exc_info()
            traceback.print_exc()
            pdb.post_mortem(tb)
    else:
        bombs()
```

Using –pdb
──────────

```
python yourfile.py --pdb
```

Image: running this example with and without –pdb flag <https://images.waylonwalker.com/using-pdb-flag-from-cli.png>