Fri, 24 Jul 2009 21:17:26 +0200: Kamil Dudka <[email protected]> wrote:
> We can do the same with: > > $ readlink -f "$path0/$path1" I just tried "readlink -f a/b" and it prints nothing if the directory "a" doesn't exist in the current directly. > The algebra seems really strange to me. Has the '-' operator usual semantic > of unary '-' (meaning inverse element with regards to binary operation '+')? > Then should the following be always true: > 1. -(-a) == a > 2. a - b == a + (-b) They are true. > Do we have any real life use-case for the operator '-'? I think concatenation > with "/.." and/or sed invocation are mostly sufficient. > > > 3. Form a list of path with binary operator ' '. > > > > <path0> <path1> > > > > This form a list of two paths. > > $ printf "%s %s\n" `readlink -fn $path1` `readlink -fn $path2` > > > 4. Distribute concatenation and elimination operation onto a list of > > paths with a binary operator *. > > > > <path0> * ( <path1> <path2> ) > > > > is equivalent to > > > > <path0> + <path1> <path0> + <path2> > > > > ( <path0> <path1> ) * - <path2> > > > > is equivalent to > > > > <path0> - <path2> <path1> - <path2> > > We can do this by running the above mentioned in a loop (using shell). I fully agree with you that all these are doable with existing commands and scripting. What I am proposing is a dedicated command for path manipulation with concise expression. -Tak _______________________________________________ Bug-coreutils mailing list [email protected] http://lists.gnu.org/mailman/listinfo/bug-coreutils
