In <87fx6mkfhn....@merciadriluca-station.merciadriluca>, Merciadri Luca wrote: >$ cp *.* >is equivalent to >$ cd . ; cp *
Not true.
The second misses a file named "foo", as the shell glob "*.*" only matches
filenames with at least one '.' character in their name.
>$ cp .*
>is equivalent to
>$ cd . ; cp *
Again, not true.
The second misses a file named ".foo", as wildcards ('?' and '*' characters)
in shell globs do not match a '.' character in the first position. (This is
part of the "hidden" aspect of dot-files.)
>A third case is
>$ cp .[a-zA-Z0-9]*
>which is equivalent to copy everything beginning with a dot, and
>ending with whatever you can imagine.
Again, not true.
The first misses a file named ".$ntfs$protected", as the bracket/range
expression only catches letters and digits, and may not catch all of them
depending on the collation settings in the environment.
>Consequently, using
>$ cp .[a-zA-Z0-9]*
>
>and the mere (after or before)
>$ cp *
>
>should copy all the files of a directory to another (they were
>evidently not specified here, as it is trivial stuff).
I would use (cp {,.[!.]}* "$destination") in shells that do brace expansion
before filename expansion ("globbing"), e.g. bash and zsh. In other shells,
e.g. those without brace expansion, I would write it out as (cp * .[!.]*
"$destination").
An alternative I got in the habit of using instead of remembering the "line
noise" above is doing (cp -r "$src/." "$destination"), which is, for me,
semantically closer to what I *mean* than writing something that expands to
all the entries in the directory.
>I could be wrong for at least one of these facts. If so, we can
>discuss on it. The syntax is actually weird when one begins to play
>with special files. For sure.
The various expansions done by the shell and the order they are done in is
well-documented by the bash info pages, the zsh man pages, and (for POSIX-
compliant shells) the Single Unix Specification.
They are not necessarily easy to understand, but I wouldn't use the word
"weird". I think "complex" is a better adjective.
--
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