openharmony4.0release编译出错

openharmony4.0release编译，完全按照gitee的步骤，为什么出现下面的错误：

[OHOS INFO] [626/20649] ACTION //third_party/musl/ndk_script:windows_x86_64(//build/toolchain/ohos:ohos_clang_arm64)

[OHOS ERROR] [617/20649] ACTION //arkcompiler/ets_frontend/es2panda:gen_keywords_headers(//build/toolchain/linux:clang_x64)

[OHOS ERROR] FAILED: clang_x64/obj/arkcompiler/ets_frontend/es2panda/gen/keywords.h  

[OHOS ERROR] /usr/bin/env ../../arkcompiler/ets_frontend/es2panda/scripts/gen_keywords.sh -g /home/fttech/openharmony4.0r/arkcompiler/ets_frontend/es2panda/lexer/scripts/keywords.rb -t ../../arkcompiler/ets_frontend/es2panda/lexer/templates/keywords.h.erb -o keywords.h -d /home/fttech/openharmony4.0r/out/sdk/clang_x64/obj/arkcompiler/ets_frontend/es2panda/gen

[OHOS ERROR] ../../arkcompiler/ets_frontend/es2panda/scripts/gen_keywords.sh: 行 46: ruby：未找到命令

[OHOS ERROR] Traceback (most recent call last):

[OHOS ERROR]   File "/home/fttech/openharmony4.0r/build/hb/services/ninja.py", line 49, in _execute_ninja_cmd

[OHOS ERROR]     SystemUtil.exec_command(

[OHOS ERROR]   File "/home/fttech/openharmony4.0r/build/hb/util/system_util.py", line 63, in exec_command

[OHOS ERROR]     raise OHOSException(

[OHOS ERROR] exceptions.ohos_exception.OHOSException: Please check build log in /home/fttech/openharmony4.0r/out/sdk/build.log

[OHOS ERROR]