我想知道$?的功能？
例如，如果一个变量有这个值，比如VARIABLE=$?
如果是运算符，当然有办法知道这种运算符。
【问题讨论】：
$? 在原始问题中包含在**...** 中，清楚地表明问题是关于那个特定的特殊参数。
$?，而不是$，很抱歉造成混淆。
$?给你最后的返回码
【讨论】：
$# Stores the number of command-line arguments that
were passed to the shell program.
$? Stores the exit value of the last command that was
executed.
$0 Stores the first word of the entered command (the
name of the shell program).
$* Stores all the arguments that were entered on the
command line ($1 $2 ...).
"$@" Stores all the arguments that were entered
on the command line, individually quoted ("$1" "$2" ...).
【讨论】：