第一个 '.' 是什么意思？' 中的意思。~/.bashrc'?

Question

我看到一篇关于修复你的别名的帖子.bashrc。

他说在你把你的别名放进去后.bashrc，你需要使用：

. ~/.bashrc

我不太明白第一个点(' . ') 在这里做什么。它的功能是什么，叫什么名字？

Answer 1

如果您想在 bash 中检查某些内容，请使用 type和man。

在您的情况下，您想知道什么是 .

$ type .
. is a shell builtin

shell 内置意味着. 在里面bash shell。您可以在bash手册页中找到有关 shell 内置函数的信息。有一大段SHELL BUILTIN COMMANDS

$ man bash

SHELL BUILTIN COMMANDS
       Unless otherwise noted, each builtin command documented in this section
       as accepting options preceded by - accepts -- to signify the end of the
       options.   The  :, true, false, and test builtins do not accept options
       and do not treat -- specially.  The exit, logout, break, continue, let,
       and  shift builtins accept and process arguments beginning with - with?
       out requiring --.  Other builtins that accept  arguments  but  are  not
       specified  as accepting options interpret arguments beginning with - as
       invalid options and require -- to prevent this interpretation.
       : [arguments]
              No effect; the command does nothing beyond  expanding  arguments
              and  performing any specified redirections.  A zero exit code is
              returned.

        .  filename [arguments]
       source filename [arguments]
              Read and execute commands from filename  in  the  current  shell
              environment  and return the exit status of the last command exe?
              cuted from filename.  If filename  does  not  contain  a  slash,
              filenames  in  PATH  are  used  to find the directory containing
              filename.  The file searched for in PATH need not be executable.
              When  bash  is  not  in  posix  mode,  the  current directory is
              searched if no file is found in PATH.  If the sourcepath  option
              to  the  shopt  builtin  command  is turned off, the PATH is not
              searched.  If any arguments are supplied, they become the  posi?
              tional  parameters  when  filename  is  executed.  Otherwise the
              positional parameters are unchanged.  The return status  is  the
              status  of  the  last  command exited within the script (0 if no
              commands are executed), and false if filename is  not  found  or
              cannot be read.

Answer 2

有趣...名称似乎是dot-command，在您的情况下，它将 .bashrc 包含到调用 shell 程序中（在您的情况下，您的 bash 环境）。当您从命令行调用它时，它会更新您的环境变量，因为变量是在 .bashrc 中设置的。

echo "FOO=bar" > test
echo $FOO

没有结果，环境变量未设置。但是在您获取“测试”文件之后：

. test

设置了环境变量 FOO 并且

echo $FOO

导致输出

bar

我在这里找到了以下信息：

获取文件（点命令）将代码导入脚本，附加到脚本（与 C 程序中的 #include 指令效果相同）。最终结果与“来源”代码行实际存在于脚本主体中一样。这在多个脚本使用公共数据文件或函数库的情况下很有用。

另外，请参阅此问题。在 bash 中，.与source.