shell - How does "*.txt" regex work with ls command? -

shell - How does "*.txt" regex work with ls command? -

i have file name

atxt

and running command

ls *.txt

ideally should match . 'a' , * 0 character, returning files like

a.txt, b.txt

why here ls treating . literal dot, rater character of regex.

it's called file globbing, not regular expression.

although both back upwards wildcards "?", "*", have different schemes.

for example, "a*" in glob matches filename begins "a", in regex matches string has 0 or more of letter "a". difference wildcard "?" , "*" in regex must have preceding element, while it's unnecessary in globbing.

as lastly question, dot "." has not special meaning in globbing, it's literal dot. match 1 unknown character in globbing, 1 utilize "?".

regex shell unix ls