So I have to modify a batch script which I notice has this style of parsing command-line flags, for example:

if /I {%1} == {-d} (

Is there any reason why curly braces are used? As far as I know, they don't really have any significance in batch scripts. Interestingly, the commit history shows that curly braces were introduced after code review, and the pre-review version used square brackets:

if /I [%1] == [-d] (

Initial coders/reviewers are gone, so I'm asking here why these braces/brackets would be necessary, and whether it's any different than using doublequotes instead, or even no quotes at all.

CodePudding user response：

It's one of many methods used to protect against %1 being unspecified, which leads to its being replaced by nothing and hence a syntax error as if == whatever ( is illegal. Braces were used, brackets, simply pre/succeeding with a character... Normally, "quoting both sides" of the comparison operator is used.

Or

set "somevar=%~1"
if defined somevar ...