“来源”是做什么的？

$ whatis source
source: nothing appropriate.
$ man source
No manual entry for source
$ source
bash: source: filename argument required
source: usage: source filename [arguments]

它存在，并且可以运行。为什么在Ubuntu中没有关于它的任何文档？它有什么作用？如何安装有关它的文档？

source是bash shell内置命令，它执行当前shell中作为参数传递的文件的内容。在.（句点）中有一个同义词。

句法

. filename [arguments]

source filename [arguments]

小心！./并且source都不太一样。

• ./script将脚本作为可执行文件运行，启动新的外壳程序以运行该脚本
• source script在当前Shell环境中从文件名读取并执行命令

注意：./script不是. script，而是. script==source script

https://askubuntu.com/questions/182012/is-there-a-difference-between-and-source-in-bash-after-all?lq=1

了解“ type”命令很有用：

> type source
source is a shell builtin

每当内置外壳的东西时，就该做man bash。

。（句点）是bash shell内置命令，该命令在当前shell中执行作为参数传递的文件中的命令。“源”是“。”的同义词。

从Bash手册页：

. 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, file
       names in PATH are used to find the  directory  containing  file‐
       name.   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.

“源”是“”的长版本。命令。在bash提示符下，可以执行以下操作：

source ~/.bashrc

重新加载当前运行的bash的bash设置（已更改？）。

简短的版本是：

. ~/.bashrc

手册页：

. 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 executed from filename. If 
    filename does not contain a slash, file names 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 short
    builtin command is turned off, the PATH is not searched. If any arguments
    are supplied, they become the positional 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. 

source该命令在当前 shell环境中执行提供的脚本（不是强制执行权限），而在新 shell中执行提供的可执行脚本。./

source命令确实有一个同义词. filename。

为了更加清楚，请看下面的脚本，该脚本设置了别名。

make_alias

#! /bin/bash

alias myproject='cd ~/Documents/Projects/2015/NewProject'

现在，我们有两个选择来执行此脚本。但是只有一个选项，可以在这两个选项之间创建当前shell所需的别名。

选项1： ./make_alias

首先使脚本可执行。

chmod +x make_alias

执行

./make_alias

校验

alias

输出量

**nothing**

哎呀！别名随着新的外壳而消失了。

让我们来看第二个选项。

选项2： source make_alias

执行

source make_alias

要么

. make_alias

校验

alias

输出量

alias myproject='cd ~/Documents/Projects/2015/NewProject'

是的，别名已设置。

如有疑问，最好的方法是使用以下info命令：

[root@abc ~]# info source

BASH 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, file
              names  in  PATH  are used to find the directory containing file-
              name.  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.

在外壳程序中键入命令“ help source”。

您将获得如下输出：

source: source filename [arguments]

Execute commands from a file in the current shell.

Read and execute commands from FILENAME in the current shell.  The
entries in $PATH are used to find the directory containing FILENAME.
If any ARGUMENTS are supplied, they become the positional parameters
when FILENAME is executed.

Exit Status:
Returns the status of the last command executed in FILENAME; fails if
FILENAME cannot be read.

从Linux文档项目，高级Bash脚本指南，
第15章- 内部命令和内建函数：

源，。（点命令）：
从命令行调用此命令时，将执行脚本。在脚本中，源文件名将加载文件文件名。源文件（点命令）会将代码导入脚本，并附加到脚本（与C程序中的#include指令相同）。最终结果与脚本主体中实际存在“源”代码行相同。当多个脚本使用公共数据文件或函数库时，这很有用。
如果源文件本身是可执行脚本，则它将运行，然后将控制权返回给调用它的脚本。为此，源可执行脚本可以使用返回值。

因此，对于那些熟悉C编程语言的人来说，采购文件具有类似于#include指令的效果。

还要注意，您可以将位置参数传递给要获取的文件，例如：

$ source $filename $arg1 arg2

应当指出的是，虽然是一个真棒命令，既不source也不是它的简写.将采购 超过一个文件，意思

source *.sh

要么

. script1.sh script2.sh

将无法正常工作。

我们可以使用for循环进行回退，但是它将多次执行该可执行文件，创建多个命令或执行该命令。

结论：source不会将多个文件作为输入。该论点必须是一个。

真烂，恕我直言。

使用source，您可以将另一个文件中的变量或函数传递到脚本中并使用它们，而无需再次编写它们。

FI：

#!/bin/bash

source /etc/environment

source /myscripts/jetty-common/config/jetty-functions.sh

干杯