根据这个：Do a “git export” (like “svn export”)?，这张照片有什么问题？：
user@machine /cygdrive/c/Ws/PROJECT_master_coverage : git archive master | bzip2 > /cygdrive/c/Ws/PROJECT_master_coverage.tar.bz2
fatal: Not a valid object name
user@machine /cygdrive/c/Ws/PROJECT_master_coverage : git archive --format zip --output /cygdrive/c/Ws/PROJECT_master_coverage.zip master
fatal: Not a valid object name
user@machine /cygdrive/c/Ws/PROJECT_master_coverage : git archive master | tar -x -C /cygdrive/c/Ws/PROJECT_master_coverage.tgz
fatal: Not a valid object name
tar: This does not look like a tar archive
tar: Exiting with failure status due to previous errors