On Thu, May 6, 2010 at 5:36 PM, Bob Proulx <b...@proulx.com> wrote: > Peng Yu wrote: >> Is there a way to overload operators like '>' and '>>' in bash, just >> as overloading in C++, etc. Suppose I have already made some bash >> program using '>' and '>>' without thinking about symbolic link, but I >> begin aware of them later. I would be cumbersome to add a test >> statement and deciding whether 'rm' or not for each usage of '>' and >> '>>'. > > It sounds to me like you are trying to implement a "script space" > version of copy-on-write semantics? Perhaps you should investigate > using one of the filesystem based solutions. It would probably give > you a better result. > >> A more general question is how to change the behavior of a program >> (for example compiled from C code) to delete symbolic link and write a >> new file, without recompiling the program. > > A Comment: Symbolic links are designed to be transparent. Normal > programs are not aware of them. > > You could probably create an LD_PRELOAD library to intercept file > modification calls and then handle them in your own code. But I think > it would be difficult to do it all completely correctly and not to > introduce bugs. I advise against it.
Would you please elaborate a little more on how to use LD_PRELOAD to modify the call. If the library (for example, 'open' from stdlib.h) is statically compiled in the binary, is LD_PRELOAD going to replace it with a different 'open' function? -- Regards, Peng
