-bash 是什么意思？

Question

我echo $0在 tty1 中输入命令，它返回-bash，为什么不bash呢？

Answer 1

它表明它bash是作为登录 shell 启动的。从man bash，部分INVOCATION（强调我的）：

A login shell is one whose first character of argument zero is a -,  or
one started with the --login option.
...
When bash is invoked as an interactive login shell, or as a  non-inter?
active  shell with the --login option, it first reads and executes com?
mands from the file /etc/profile, if that file exists.   After  reading
that file, it looks for ~/.bash_profile, ~/.bash_login, and ~/.profile,
in that order, and reads and executes commands from the first one  that
exists  and  is  readable.  The --noprofile option may be used when the
shell is started to inhibit this behavior.

When a login shell exits, bash reads and  executes  commands  from   the
file ~/.bash_logout, if it exists.

$0，当然，是参数零。

在 Ubuntu 中，通常.profile存在.bash_profile和.bash_login不存在。因此，登录 shell 读取.profile.

也可以看看：

• 什么是登录和非登录 shell？
• 登录 Shell 和非登录 Shell 的区别？