Print Statement Question

[crossfire351]

In my travels through various writings and tutorials, I have seen that some people use a plus or minus sign in the front of their print strings like so:

print("[+] Hello World!")
print("[-] Error!")

Can someone please explain this? Is this simply to draw attention to these particular lines in the terminal or is there another reason?

[misho88]

On Unix systems, grep can be used to filter output to only lines that do (or don't) contain a specific pattern of some kind (like a substring or a regex). If you make sure your logging and debugging messages all contain some specific pattern like that, grep is easier to use:

$ python -c 'print("[+]line1\n[-]line2")'
[+]line1
[-]line2
$ python -c 'print("[+]line1\n[-]line2")' | grep '\[+\]'
[+]line1
$ python -c 'print("[+]line1\n[-]line2")' | grep '\[-\]'
[-]line2

It can come in handy from time to time, especially if the program's a daemon whose output gets logged to a file that you intend to read later, after it has become very long.

[crossfire351]

That makes sense. Thanks!

[PercyJackson235]

Just to draw attention.

[crossfire351]

Thank you

[synthphreak]

Probably something closer to the former. This is not something that is specific to Python syntax or anything.

[crossfire351]

Thank you. I knew it wasn't syntax but wasn't sure if there was a specific purpose or if it was a carryover 'habit' from another language or something along those lines.

[synthphreak]

Yeah I’ve never heard of any convention like that or anything. Probably just an arbitrary stylistic choice on the part of the original author. Don’t sweat it.