运行“内置”有什么作用？

Question

很简单的问题，真的...

内置？

运行时会发生什么：builtin?

的返回类型echo $?是0。

这意味着该命令很可能已成功运行。

那么，跑步到底有什么作用builtin呢？

Answer 1

当您希望将 shell 内置函数重新实现为 shell 函数，但需要在函数内执行内置函数时，这很有用。

$ type echo
echo is a shell builtin

$ function echo(){ builtin echo "'$1'"; }

$ echo hi
'hi'

help builtin 

builtin: builtin [shell-builtin [arg ...]] 执行 shell 内置函数。

Execute SHELL-BUILTIN with arguments ARGs without performing command
lookup.  This is useful when you wish to reimplement a shell builtin
as a shell function, but need to execute the builtin within the function.

Exit Status:
Returns the exit status of SHELL-BUILTIN, or false if SHELL-BUILTIN is
not a shell builtin.