The command echo {1..3}-{1,2}
prints 1-1 1-2 2-1 2-2 3-1 3-2
. I understand the way those curly braces can be used. But what actually are they?
Is it the job of sh
/ bash
to parse/expand them and deliver the expanded version to the executed program?
If so, what other tricks can it do and is there a specification?
Also, is there a name for it?
Is ls *.txt
handled in a similar way internally?
Is there a way to achieve an n-times repetition of an argument? Like (not working, of course, only a concept): cat test.pdf{*3}
⇒ cat test.pdf test.pdf test.pdf
?
bash
. You can read on it in manual.