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Comment by lohfu | Hacker News Reader

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lohfu·

Really? I thought the shell could only expand globs if it matches files on the local file system?

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The feature is called brace expansion:

https://www.gnu.org/software/bash/manual/html_node/Brace-Exp...

You may also be interested in yet another powerful feature that is parameter expansion:

https://www.gnu.org/software/bash/manual/html_node/Shell-Par...

Filename expansion (nitpick: often mistaken for globbing) is performed last:

https://www.gnu.org/software/bash/manual/html_node/Filename-...

> nitpick: often mistaken for globbing

What exactly would you call globbing if not the feature that is controlled using the nullglob, failglob, nocaseglob and dotglob options as well as the GLOBIGNORE variable.

Globbing has an ambivalent definition given that it’s mostly used for filename matches (especially given its origin as the glob command), but it’s really a specific form of pattern matching using wildcards such as * and ?, it need not apply only to filenames or paths on the filesystem: this matching is also used to match strings in case/in/esac constructs and test’s == !=

https://www.gnu.org/software/bash/manual/bash.html#Condition...

I guess one could say globbing is applying this pattern matching to filter a list.

You're right regarding glob functionality, but the curly braces are a separate shell feature. The most useful idiom I use it for is renaming or copying, e.g.:

cp filename{,_backup}

Thoae aren't globs, if you put an asterisk there it would not work.

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