bash - 最短的非空 bash quine

Question

最短的 bash quine 是空字符串:

$ bash -c ''
$ 

生成自己的源代码作为输出的最短的非空 bash 脚本是什么？

Answer 1

19 个字符:

$echo 'echo $BASH_COMMAND' > quine
$ wc -c quine
19 quine
$ cat quine
echo $BASH_COMMAND
$ bash quine
echo $BASH_COMMAND
$

字符数包括源中的换行符(因为它是在输出中产生的)。

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如果您之前没有听说过$BASH_COMMAND，the manual说:

BASH_COMMAND

The command currently being executed or about to be executed, unless the shell is executing a command as the result of a trap, in which case it is the command executing at the time of the trap.