When an argument is passed that does not exist, `ls` always prints the
directory name for the existing ones, even if there is only one
remaining directory that is listed.
`ls` prints a warning if a non-flag argument is specified that does not
exist.
Previously ls-show-hidden assumed that all arguments that are neither a
directory nor an otherwise existing file are flags. As all flags are
passed to the ls call the warning still got printed, but this also lead
to the current working directory (i.e. `.`) being added to the
directories to process.
If `ls` expects an argument to a flag, it is always passed in the format
`--flag=arg` where the equal sign is mandatory. This makes it possible
to simply filter out all flags (and their arguments) from the other
arguments without needing to know which flags take an argument and which
don't.
Fix this behaviour by printing the same warning as `ls` does when an
argument is neither a flag, nor a directory nor an existing file. Also
only add `.` to the directories if *really* only flags were passed.
By adding a shebang to the scripts they can be executed directly without
an interactive shell. The shebang also makes vims modeline that only set
the filetype obsolete.
Fix behavior to match ls's when the -d flag but no files or directories
were passed.
Fix bug that the function thinks -d is passed when a long option that
contains a 'd' (as --group-directories-first) is specified and thus
just emulates plain `ls` in that case.
