新聞財經娛樂♬資訊 News Economy

Could anyone give a clear picture between $0 and $_
root@localhost ~]# echo $0
-bash
[root@localhost ~]# echo $_
-bash
[root@localhost ~]# greet
enter nameIllegal variable name.
[root@localhost ~]# echo $_
greet
[root@localhost ~]# echo $0
-bash
[root@localhost ~]#

Its called bash special parameters .
If you could google it you would get more info.
I can't  past the link as its violating EE rules

http://www.gnu.org/software/bash/manual/html_node/Special-Parameters.html

$0 is the first argument,    "echo" or script file name or script type  depend on your system
$_   is Last argument of the previous command.

Hope it help

DUncan