Coding day

Yesterday, I went work as usual and did coding.
I noticed that the log output from the program I wrote the other day contained strange values.
The value should only be 0 or 1.
I thought about where in the program there might be a problem.
How the values are obtained is by using commands from devices in the same network.
I thought I got the expected result in one line after executing the command.
Actually, it wasn't.
The result obtained after executing the command was not always a single line, and sometimes it contained something different from what was expected.
The results of the command contained something unexpected. The log should have contained strange values.
I immediately rewrote the program.