CODEWITHSUNDEEP
pythonpython-3.xdebuggingpycharm
Kelly
Kelly

Reputation: 163

How can i debug my code from the terminal?

How can i debug my python code step by step if i want to by placing the red dots from terminal as i used to do that on PyCharm but having difficulties with the debug when i run my file from the python terminal using the command

python testings.py --annotations=input.csv

Upvotes: 1

Views: 10558

Answers (1)

Frederik Petersen
Frederik Petersen

Reputation: 478

You can use Pdb for debugging using the command line.

It has a argument b(reak) that allows you to specify a line number where you want to have a break point.

It's definitely more cumbersome than using a proper IDE, but certainly helps in certain situations.

Example:

Simple example script (example.py):

a = 2
b = 5

c = a + b

print("{0} + {1} = {2}".format(a, b, c))

Starting debugger:

python3 -m pdb example.py

Now the debugger will start and will point to the first line. We can then use the commands (see documentation linked above) to step through the code. An example:

> /home/[...]/example.py(1)<module>()
-> a = 2
(Pdb) b 4
Breakpoint 1 at /home/[...]/example.py:4
(Pdb) c
> /home/[...]/example.py(4)<module>()
-> c = a + b
(Pdb) s
> /home/[...]/example.py(6)<module>()
-> print("{0} + {1} = {2}".format(a, b, c))
(Pdb) p c
7
(Pdb)

Explanation: Every line with (Pdb) is a prompt where you can enter commands. Here are the commands I entered:

  1. b 4 sets a breakpoint at line 4. This is confirmed by the next line.
  2. c continues running the script until the next breakpoint is hit. As you can see in the next line, the debugger now stops at c = a + b which is line 4 of the script.
  3. s performs one step, so we are now at the print statement.
  4. p c prints the value of expression "c" which in this case is simply the value of the variable c: 7

For more commands and their explanations, again, take look at the official documentation. Hope this serves as a very basic introduction on how to use Pdb.

Upvotes: 2

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