6 ms·

It's pretty much useless for the same purpose: $ which ls /usr/bin/ls $ type ls ls is aliased to `ls --color=auto' $ command -v ls alia

• jwmhjwmh 5y ago
  I think aliases are only used in interactive shells: $ sh -c 'command -v ls' /bin/ls
• scbrg 5y ago
  This is a very unlikely output when run from a script using the /bin/sh interpreter on Debian, though. If that is the output you've gone out of your way to create an alias in a script, in which case it's reasonable output. It is what will happen when the script runs that command, after all.
  • guerrilla 5y ago
    I'm certain there's masses of code that depends on `which` responding the way it does and scripts with aliases in them regardless of whether that was the right way to do it or not, so your point is probably irrelevant in the grand scheme of things. Think about all that enterprise install and setup crap. People still depend on that spaghetti trash working.
• Taywee 5y ago
  That depends on whether your shell has a built-in which or not. Mine says % which ls ls: aliased to /bin/ls --color=auto Which makes way more sense. Your "which" is not telling you what will actually be executed when you run the `ls` command there. `command`, on the other hand, is guaranteed to be a built-in, has consistent behavior, and has defined, consistent output, unlike `which`. What `which` outputs will be different depending on shell and what implementation of `which` you actually have installed.
  • guerrilla 5y ago
    That depends on which which you mean. Which on GNU has always been this: NAME which - shows the full path of (shell) commands. DESCRIPTION Which takes one or more arguments. For each of its arguments it prints to stdout the full path of the executables that would have been executed when this argument had been entered at the shell prompt. It does this by searching for an executable or script in the directories listed in the environment vari‐ able PATH using the same algorithm as bash(1).
    • Taywee 5y ago
      Unless you're using a shell that subverts that by providing its own built-in, like Zsh, which is allowed because there is no standard for `which`, and depending on its behavior can be problematic and inherently non-portable. That description is also doesn't correctly describe the behavior of the command if the shell has any aliases or built-ins of that name. If you have an alias that points to a different command, then `which` is distinctly not printing the executable that would have been executed.
      • guerrilla 5y ago
        As I said, it depends on which which you mean. In this case, Debian is changing it's behavior away from how it's been for 28 years or whatever and breaking heaps of code and people's habits in the process.
        • Taywee 5y ago
          Yes, you're right. I think it's fine to depend on the existing which behavior for the current use cases. I just disagree that the behavior is really more useful than `command -v` for any sort of build or scripting purposes. It's definitely more useful as a user-facing utility to have a very recognizable name, like `which`. I'm one of the people who had never heard of `command -v` before now, and I'd used `which` for scripting, because I assumed it was standardized. I just don't see much use case for a shell command that finds a command in the path while specifically ignoring all aliases, functions, and built-ins over something like `command -v`. > In this case, Debian is changing it's behavior away from how it's been for 28 years In this case, Debian has voted to keep it the same: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=994275 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=994275