Re: Long filenames in DOS/Windows and Unix/Linux

On 05.09.2024 11:29, Ralf Fassel wrote:

* Richard Kettlewell <invalid@invalid.invalid>
| Keith Thompson <Keith.S.Thompson+u@gmail.com> writes:
| > [...] For example, I might type something like:
| >
| >     for file in * ; do cp -p $file $file.bak ; done

Quoting is generally the standard way to be on the safe side...

  for file in * ; do cp -p "$file" "$file.bak" ; done

| That’s the heart of the matter. Field splitting happens after parameter
| expansion. 
 
Only sometimes it doesn't :-)
 
    $ foo="foo bar"
    $ bar=$foo
 
No problem with the space in the expanded value here!
 
    $ echo $bar
    foo bar

There is a problem also with 'echo'...!

space="foo bar"
two_spaces="two  spaces"
a_tab="a tab"

# all the IFSs get collapsed in:
echo $space
echo $two_spaces
echo $a_tab

# correct way to handle that:
echo "$space"
echo "$two_spaces"
echo "$a_tab"

 
but of course:
   ls $bar
   ls: cannot access 'foo': No such file or directory
   ls: cannot access 'bar': No such file or directory
 
It's documented in bash(1):
 
  PARAMETERS
       [...]
       A variable may be assigned to by a statement of the form
 
              name=[value]
 
       [...] Word  splitting is not performed, with the exception of
       "$@" as explained below under Special Parameters.
 
but I find it confusing nevertheless.

It's not that confusing if you know the difference between a shell
construct (that doesn't require quotes) and "the all rest" that
needs (for the general case) quotes. If in doubt there's the rule
of thumb to always use quotes.

Janis

 
R'