4 ms·

While I agree that v0.1 should support stdin/stdout, I don't know that you are serving all of your users well by limiting i/o to ONLY stdin/out.

• lucb1e 10y ago
  The two applications for specifying files on the command line is when: they actually do something with that file (e.g. move the file) or when you operate on multiple files and/or directories (e.g. backup application). Otherwise it still might be useful, but in general it's kind of unnecessary. It adds logic to your application that it doesn't need, which violates "do one thing, and one thing very well" (albeit only a very small violation).
  • jpitz 10y ago
    ISTM that you're arguing from a perspective of intrinsic necessity. Your argument is that, anyone can cat a file into my utility, if they need that functionality. Sure. However, for example, GNU sort doesn't work that way. Most utilities don't work that way. Most utilities accept a file as an source of input, and most of those don't act on the inode. That's the status quo.
    • marvy 10y ago
      sort is a bad example: to support sorting in-place, it has to know the file name. Pity the user who typed sort < bigfile > bigfile for said user just lost a file.
      • d0mine 10y ago
        A general solution is something like: $ sort "$name" | sponge "$name" Check whether: $ sort -o "$name" "$name" works with your version of the sort utility.
      • shabble 10y ago
        This has bitten me occasionally, even though I know the workarounds (tempfiles or pipe-consumers like sponge(1)). I'm wondering if there's any practical use for the behaviour, or if it's worth hacking a shell such that it produces a warning/interactive confirm prompt for it (or transparently buffers to DWIM maybe?)
        • eichin 10y ago
          It's pretty common to `set -o noclobber` in beginner dotfiles; doing deferred-open-if-exists is an interesting idea that would probably get a lot of resistance :-)
  • dllthomas 10y ago
    A third is "it uses multiple files (and the behavior can't be replicated by concatenating them)." Picking one input to still be consumed from stdin can make sense, though. A special case of this is config files, which are almost never read from stdin (they usually have a default location or several).
• Annatar 10y ago
  Outputting to stdout gives the control and power to the user - if they want it in a file which they want to name, they can do that; if they want to pass the output as input to another application - they can do that too. There are few usage scenarios where such behavior isn't enough, like for example fsck, but even there this paradigm is flexible enough to work - for such applications could be split into an analyzer and a repair program. There is nothing stopping one from outputting a binary data stream on stdout; Lots of applications do exactly that on UNIX, compressors come to mind. What use case have you where stdout/stdin/stderr isn't enough on an operating system family where the core paradigm of usage is that everything is a binary stream of data?
  • jpitz 10y ago
    > Outputting to stdout gives the control and power to the user - if they want it in a file which they want to name, they can do that; if they want to pass the output as input to another application - they can do that too. Please note that we already agree here. > What use case have you where stdout/stdin/stderr isn't enough on an operating system family where the core paradigm of usage is that everything is a binary stream of data? My argument isn't that I have a use case where it 'isn't enough.' My argument is that many people come to a cli utility expecting that <foo /path/to/myfile> simply works.
    • Annatar 10y ago
      My argument is that many people come to a cli utility expecting that <foo /path/to/myfile> simply works. So are for or against that? If you're for the < /path/to/my/file argument, then we are in complete agreement. A command line application should read from stdin where that applies.
      • dllthomas 10y ago
        It seems to me there was confusion here caused by an unfortunate choice of angle brackets for quoting. I think `foo /path/to/myfile` is what the parent was trying to say.