ls pattern matching

Question

I know that [] is working in ls pattern matching:

$ ls
foo.c  foo.h
$ ls foo.[ch]
foo.c  foo.h

but I cannot find where this is documented.

I would like to know the syntax that would match these:

$ ls
foo.asd  foo.qwe

This is the best guess I had: ls foo.[{asd}{qwe}]. It did not work.

Solution 1

I think you are looking for the brace expansion {asd,qwe}:

$ ls foo.{asd,qwe}
foo.asd  foo.qwe

Solution 2

The globbing pattern would be ls foo.@(asd|qwe). This works

• out of the box in ksh;
• in bash also if "extended globbing" is activated with shopt -s extglob;
• in zsh if ksh-style globs are activated with setopt ksh_glob.

Comments

[Janis]

It is not "pattern matching" from ls but "shell globbing"; see the shell documentation for all the details. ls gets just to see what the shell expands.

[Gauthier]

This is what I was looking for. @Janis comment helped me find documentation, eg here: linux.die.net/Linux-CLI/x11655.htm

[Janis]

Note that this is not pattern matching, but brace expansion; even if it works for this specific case you cannot match arbitrary patterns with it.

[heemayl]

@Janis: I think OP is looking for this actually, the examples on the question also suggests so..probably he/she could not clarified query enough..see OP's comment above..

[Janis]

@heemayl; as said, it seems to suffice for his needs. But in his question he clearly spoke about "pattern matching" and "the syntax that would match".

[Gauthier]

According to this: linux.die.net/Linux-CLI/x11655.htm , this brace expansion qualifies as standard wildcards or globbing pattern. I am not sure how "pattern matching" differs from "globbing pattern". Strangely, man 7 glob describes [] but not {}.

[Peter.O]

link to Bash Extended Globbing

[heemayl]

@Gauthier: globbing is synonymous to pattern matching in shell, i think what Janis meant is to use extented pattern matching using extended glob..

[Janis]

@heemayl; yes, this was the semantics. @Gauhier; no, brace expansion is not equivalent to or from the cathegory "pattern matching". Brance expansion is just a textual expansion and will produce an error if used in a globbing context and one of the generated file names is not existing. Observe the difference of ls *.{foo,bar,baz} and *.@(foo|bar|baz) in case there's no *.baz file. Similarly the globbing pattern *.[ch] is not equivalent to the brace expansion *.{c,h}. - That is the main reason why I would not (or only in very specific cases) suggest to use brace expansion for globbing.