>>> Note that some crippled shells (like on Windows) don't allow such >>> piping; you have to use temporary files instead: >> >> Eh??? Standard cmd.exe, or even the older command.com, should be >> well able handle such a pipe, provided the programs can be found in >> the PATH. > > OK, fine to hear the opposite. Thanks. BTW, how many pipes are > allowed in a single command?
AFAIK, there's no defined limit. A practical limitation arises from the maximum length of the CLI input buffer; with command.com (MS-DOS) this was a meagre 127 bytes; IIRC, cmd.exe (Win32) allows up to 2048. Perhaps your confusion arises from the mechanism which MS-DOS used to implement pipes; temporary files were used to capture the data in the pipeline, to pass it from one process to the next, because the single tasking nature of MS-DOS didn't allow all of the pipeline's processes to coexist. However, this use of temporary files was transparent to the user -- it just looked like a pipe, in the UNIX sense. Win32 is a fully multitasking OS, so the implementation is now much closer to the UNIX prototype, but it looks no different to the user. Regards, Keith. _______________________________________________ Groff mailing list [email protected] http://lists.gnu.org/mailman/listinfo/groff
