Decomposing file paths (and extracting other information like file size, date and time, and attributes) from a batch file

Raymond ChenAugust 3, 2017Aug 3, 201708/3/17

We saw something very similar to this during the first Batch File Week. You have a file name in an environment variable, and you want to decompose its path (say, extract the drive letter or get the file base name without any path information or extension). Or you want to get the file's size or date or attributes. The technique we saw in the ...

Why does attempting to echo an undefined environment variable result in the message “ECHO is on”?

Raymond ChenAugust 2, 2017Aug 2, 201708/2/17

From a batch file, suppose you try to echo the contents of a variable that hasn't been defined: This prints ECHO is off. What's up with that? The first half of the puzzle is knowing that if a variable is not defined, then it expands to an empty string. Therefore, after expension, the command becomes simply The second half of the puzzle is ...

The redirection can come anywhere on the line, and you can use that to get rid of the spaces

Raymond ChenAugust 1, 2017Aug 1, 201708/1/17

We saw last time that the redirection can come anywhere on the line, and we saw that unquoted paths with embedded spaces can seem to work, but in fact doesn't. And you don't notice because the command processor is not parsing the command the way you think. Another problem with redirection is the unwanted trailing spaces. If you say then the ...