Re: Why echo without quotes need to glob the file

[Greg Wooledge]

On Tue, Dec 13, 2022 at 08:45:36PM +0800, wang yuhang via wrote:
> $ touch 1
> $ echo [--hello]
> 1

> I know the main reason is that my some code is poorly written. from another 
> perspective, the builtin command `echo` has nothing to do with file, but it 
> still uses regular expressions to glob the file. I don't quite 
> understand this behavior。
> 
> 
> Could you tell me the reason for the original design ?

[--hello] is an example of a "glob", which is a pattern that can match
one or more filenames.  Other examples of globs are *.txt or foobar.[ch]

Since your glob is not quoted, the shell expands it to a list of filenames
that it matches in the current directory.

If you want [--hello] NOT to be expanded, put quotes around it.  Either
single quotes or double quotes will do.