求解决git checkout的问题

yizhengming

Xv6 sources and text
The latest xv6 source is available via

git clone git://pdos.csail.mit.edu/xv6/xv6.git

We also distribute the sources as a printed booklet with line numbers that keep everyone together during lectures. The booklet is available as xv6-rev7.pdf. To get the version corresponding to this booklet, run

git checkout -b xv6-rev7 xv6-rev7

The xv6 source code is licensed under the traditional MIT license; see the LICENSE file in the source distribution. To help students read through xv6 and learn about the main ideas in operating systems we also distribute a textbook/commentary for the latest xv6. The line numbers in this book refer to the above source booklet.

xv6 compiles using the GNU C compiler, targeted at the x86 using ELF binaries. On BSD and Linux systems, you can use the native compilers; On OS X, which doesn't use ELF binaries, you must use a cross-compiler. Xv6 does boot on real hardware, but typically we run it using the QEMU emulator. Both the GCC cross compiler and QEMU can be found on the 6.828 tools page.

按上面的说明 我在本地git checkout -b xv6-rev7 xv6-rev7  出现下面的问题

fatal: git checkout：更新路径和切换分支不兼容。
您是想要检出 '*/xv6-rev7' 但未能将其解析为提交么？

求解决(还有git checkout -b xv6-rev7 xv6-rev7中的第二个xv6-rev7是什么意思， 第一个我知道是创建一个名为xv6-rev7的本地分支，并切换到这个分支)