On Portable Software

Software portability isn’t much of an issue nowadays; standard APIs (like Win32 and POSIX), virtual machines (Java, .NET/Mono), and interpreted languages (like Ruby, Python, Perl, and PHP) mean that whatever your chosen platform, you probably don’t need to worry too much about it.

This site is generated by three shellscripts and a makefile. I originally wrote them on Debian, using GNU make and coreutils. Then, I attempted to port them to FreeBSD, with Berkeley make and userland.

Big mistake.

• GNU stat takes a long option --format to specify the output format. BSD stat takes a short option -f instead. GNU stat apparently does have a short option for it as well: -c. Your guess is as good as mine.
• The format specifications for the two versions of stat bear no resemblance to one another whatsoever.
• GNU date has an option -r to display the last-modified time of a specified file. BSD date uses -r to indicate that it should interprete the following number as seconds since epoch, and print the corresponding date.
  • Actually, that’s something I’ve missed in GNU date, especially since the GNU version’s replacement feature is just a duplication of stat’s functionality.
• GNU sed has some crazy extensions that aren’t in BSD sed, that I suspect were coded by the crack-smoking monkeys of Gnome fame.
• BSD head doesn’t let you specify relative to the end of the file like GNU head does (e.g. print all but the last two lines), although BSD tail has the equivalent (e.g. all but the first two lines).
• rms scares small children.

I’d really like to make it portable, at least between BSD and GNU, but it looks like it may be a bugger to do so.