Oh, this is a time-based format problem. The last two characters are milliseconds. Most people don’t need to do this. The format of a few minutes and a few seconds is a little more, so it is used in this way to remove the last three characters. The first 0 means that the offset is 0, that is, take the first character, start from the first character, and – 3 means to remove the last three characters. The previous 0 here can also be omitted. I understand. I don’t know if I’m wrong. I hope I don’t miss people’s children. I don’t know if you understand what I’ve said. There are such posts in the forum. You can search them. Lxmxn brother has also written such posts, and batch processing explains such usage. You must have a good look when you are free.
From set /? Help extracted from:
Will expand PATH Environment variables are then used only in the extended results from eleven Number (partial)
Displacement 10) The first five characters of a character. If no length is specified, the default length is used
Value, that is, the remainder of the variable value. If both numbers (offset and length) are negative,
The number used is the numeric length of the environment variable plus the specified offset or length.
Will extract PATH The last ten characters of the variable.
Will extract PATH All characters of the variable except the last two.
ECHO Is open.
ECHO Is open.