为什么 `which` 打印出一个脚本？

Question

which conda 或 which -a conda 打印出 conda.sh 的内容，这是一个选择 conda 可执行文件并运行它的脚本，如下面的 (1)。

我希望which打印conda的路径。这可能是也可能不是 conda.sh，但无论如何我不希望看到脚本的内容。

简单地运行 conda正确打印出conda的帮助文本，如下面的(2)。

PATH 正确地在开头包含了 conda 的目录，如 (3)。

这是 Mac 上的 zsh。

(1)

conda () {
    if [ "$#" -lt 1 ]
    then
        "$CONDA_EXE" $_CE_M $_CE_CONDA
    else
        \local cmd=""
        shift
        case "$cmd" in
            (activate | deactivate) __conda_activate "$cmd" "$@" ;;
            (install | update | upgrade | remove | uninstall) CONDA_INTERNAL_OLDPATH="${PATH}"
                __add_sys_prefix_to_path
                "$CONDA_EXE" $_CE_M $_CE_CONDA "$cmd" "$@"
                \local t1=$?
                PATH="${CONDA_INTERNAL_OLDPATH}"
                if [ $t1 = 0 ]
                then
                    __conda_reactivate
                else
                    return $t1
                fi ;;
            (*) CONDA_INTERNAL_OLDPATH="${PATH}"
                __add_sys_prefix_to_path
                "$CONDA_EXE" $_CE_M $_CE_CONDA "$cmd" "$@"
                \local t1=$?
                PATH="${CONDA_INTERNAL_OLDPATH}"
                return $t1 ;;
        esac
    fi
}

(2)

conda
usage: conda [-h] [-V] command ...

conda is a tool for managing and deploying applications, environments and packages.

Options:

positional arguments:
  command
    clean        Remove unused packages and caches.
    compare      Compare packages between conda environments.

...

(3)

/Users/user1/miniconda3/bin:/Users/user1/miniconda3/condabin:/Users/user1/gcloud/google-cloud-sdk/bin:/Users/user1/miniconda3/bin:/usr/local/opt/terraform@0.13/bin:/Users/user1/.krew/bin:/Users/user1/bin:Library/Python/3.7/bin:/Users/user1/bin:/usr/local/bin:/Library/Frameworks/Python.framework/Versions/3.9/bin:/Library/Frameworks/Python.framework/Versions/3.8/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/go/bin:/usr/local/munki:/Library/Apple/usr/bin:/Applications/Wireshark.app/Contents/MacOS:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin:/usr/local/bin:/Users/user1/executables:/Users/user1/go/bin:/Users/user1/executables/apache-maven-3.6.3/bin:/Users/user1/.local/bin

Answer 1

使用-p标志：

% which pyenv 
pyenv () {
    local command
    command="${1:-}" 
    if [ "$#" -gt 0 ]
    then
        shift
    fi
    case "$command" in
        (rehash | shell) eval "$(pyenv "sh-$command" "$@")" ;;
        (*) command pyenv "$command" "$@" ;;
    esac
}
% which -p pyenv
/usr/local/bin/pyenv
%

不过请注意，在 Zsh 上，您可以使用 whence 命令获得更多信息输出：

% whence -aSv pyenv
pyenv is a shell function from /Users/marlon/.cache/zsh-snap/eval/pyenv-init.zsh
pyenv is /usr/local/bin/pyenv -> /usr/local/bin/../Cellar/pyenv/2.0.0/bin/pyenv -> /usr/local/Cellar/pyenv/2.0.0/bin/../libexec/pyenv
%

之所以在man which中找不到-p标志，是因为在Zsh中，which是一个等价于whence -c的内置命令：

% whence -aSv which
which is a shell builtin
which is /usr/bin/which
%

如果您执行 man which，您将获得外部命令 which 的手册（在上面输出的第二行）。您可以按如下方式调用后者：

% command which pyenv
/usr/local/bin/pyenv
%

不过，whence 的输出更可靠。外部命令 which 仅搜索您的 $path，其结果可能是也可能不是您在命令行上键入命令时调用的结果。另一方面，whence -aSv 准确地告诉您将调用什么（第一行）以及有哪些替代方法。

有关更多信息，请查阅 Zsh 手册：

为什么 `which` 打印出一个脚本？

Why does `which` print out a script?

zsh