请问如何得知Shell的种类？

ebit

我的OS是HP-UX11i,显示Root的Shell为/sbin/sh,他是什么shell呢？和/usr/bin/sh有区别吗？
有什么命令来显示shell的种类和版本吗？

liuzq

hpux得root默认shell是posix，/sbin下得命令一般都是只有root权限才能用命令，通常是一些系统管理命令，而/usr/bin下得命令就是一般用户用得命令了～
每个用户登录的shell种类可以在/etc/passwd中得最后一列看到～

ebit

书上讲/usr/bin/sh为POSIX shell,那么既然/sbin/sh也是POSIX shell,何必要搞两份copy呢？ 要知道二者的inode和大小都不一样的。我看/sbin/sh未必就是POSIX shell.
迷茫中...

liuzq

还是楼主看书看的精啊，我都没注意，不好意思～
上网查了一下，发现solaris有以下这种解释

/sbin/sh和/bin/sh的区别

Both /sbin/sh and /usr/bin/sh shells are Bourne shells.

The difference is that /sbin/sh is statically linked and /usr/bin/sh is
dynamically linked. There is also /bin/sh, however /bin is just a symbolic
link to /usr/bin.

# ls -l /sbin/sh
-r-xr-xr-x 2 bin root 251712 Jul 16 1997 /sbin/sh

# file /sbin/sh
/sbin/sh: ELF 32-bit MSB executable SPARC Version 1, statically linked, stripped

# ldd /sbin/sh
ldd: /sbin/sh: file is not a dynamic executable or shared object


# ls -l /usr/bin/sh
-r-xr-xr-x 3 bin root 88620 Jul 16 1997 /usr/bin/sh

# file /usr/bin/sh
/usr/bin/sh: ELF 32-bit MSB executable SPARC Version 1, dynamically linked, stripped

# ldd /usr/bin/sh
libc.so.1 =>; /usr/lib/libc.so.1
libdl.so.1 =>; /usr/lib/libdl.so.1

Dynamically linked binaries use shared libraries during their execution. This
makes them smaller in size and when libraries get updated, the binaries will
automatically use the updated libraries.

Statically linked binaries contain all the code within them. They do not
use shared libraries at all. This makes them larger in size. The useful thing
about statically linked binaries is that they can run all by themselves as
they do not depend on shared libraries. If the system is "broken" and libraries
were removed, damaged, or /usr is not mounted, /sbin/sh can still be executed.

This is why it is recommended to use /sbin/sh as the default root shell.


想来hpux应该也同理吧，只不过把bsh改成了posix shell了～