[Google Cloud][Compute Engine]在startu-scripts上找不到Linux基本命令

Question

我在运行实例组的VM启动脚本时遇到了问题。找不到touch、cat、chmod等命令。

ubuntu@instance-template-****-1:~$ sudo google_metadata_script_runner -d --script-type startup
startup-script: INFO Starting startup scripts.
startup-script: INFO Found startup-script-url in metadata.
startup-script: INFO Downloading url from https://storage.googleapis.com/bucket-*****/startup-image to /home/ubuntu/startup-scripts/script using authentication token.
startup-script: INFO startup-script-url: /home/ubuntu
startup-script: INFO startup-script-url: /home/ubuntu
startup-script: INFO startup-script-url: /home/ubuntu/startup-scripts/script: line 11: touch: command not found
startup-script: INFO startup-script-url: /home/ubuntu/startup-scripts/script: line 12: touch: command not found
startup-script: INFO startup-script-url: /home/ubuntu/startup-scripts/script: line 13: touch: command not found
startup-script: INFO startup-script-url: /home/ubuntu/startup-scripts/script: line 15: chmod: command not found
startup-script: INFO startup-script-url: /home/ubuntu/startup-scripts/script: line 16: chmod: command not found
startup-script: INFO startup-script-url: /home/ubuntu/startup-scripts/script: line 71: ssh-keyscan: command not found
startup-script: INFO startup-script-url: /home/ubuntu/startup-scripts/script: line 72: ssh-keygen: command not found
startup-script: INFO startup-script-url: /home/ubuntu/startup-scripts/script: line 74: cat: command not found
startup-script: INFO startup-script-url: /home/ubuntu/startup-scripts/script: line 76: git: command not found
startup-script: INFO startup-script-url: /home/ubuntu/startup-scripts/script: line 78: sh: command not found
startup-script: INFO startup-script-url: Return code 127.
startup-script: INFO Finished running startup scripts.

脚本：

#!/bin/bash

PATH=/home/ubuntu

cd $PATH

touch $PATH/.ssh/id_rsa
touch $PATH/.ssh/id_rsa.pub
touch $PATH/.ssh/known_hosts

chmod 644 $PATH/.ssh/id_rsa.pub
chmod 600 $PATH/.ssh/id_rsa

echo $IDRSA > $PATH/.ssh/id_rsa
echo $IDRSA_PUB > $PATH/.ssh/id_rsa.pub

ssh-keyscan bitbucket.org >> bitbucketKey
ssh-keygen -lf bitbucketKey

cat bitbucketKey >> $PATH/.ssh/known_hosts

git clone git@bitbucket.org:repo/repo.git

sh ./repo/prepare

PROJECT_ID=$(curl "http://metadata.google.internal/computeMetadata/v1/project/numeric-project-id" -H "Metadata-Flavor: Google")

./repo/deploy/run --dev --project-id=$PROJECT_ID

Answer 1

当您设置PATH=/home/ubuntu时，它会覆盖您应该在shell中获取的PATH环境变量的值，并强制后续命令以"command not found"错误结束，因为您刚刚设置的新路径/home/ubuntu上没有用于运行这些命令的适当可执行文件。您可以通过将该变量重命名为PATH及其在脚本中出现的所有项以外的任何名称来解决此问题。您也可以使用小写形式的相同变量名。(如path=home/ubuntu)。

PATH环境变量是一个冒号分隔的目录列表，当您输入命令时，shell将搜索这些目录。程序文件(可执行文件)保存在Unix系统的许多不同位置。当您请求特定程序时，您的路径将告诉Unix shell在系统上的何处查找。

Answer 2

您在脚本中修改了路径环境：

PATH=/home/ubuntu

但是，PATH是bash的Shell变量：

PATH   The search path for commands.  It is a colon-separated list of directories in which the shell looks for commands (see
       COMMAND  EXECUTION below).  A zero-length (null) directory name in the value of PATH indicates the current directory.
       A null directory name may appear as two adjacent colons, or as an initial or trailing colon.   The  default  path  is
       system-dependent, and is set by the administrator who installs bash.  A common value is ``/usr/local/bin:
       /usr/local/sbin:/usr/bin:/usr/sbin:/bin:/sbin''.

因此，几乎所有的命令都找不到。(除非它们在/home/ubuntu下)

如果您只想将变量设置为用户文件夹，以便与脚本一起操作，请将变量名称更改为like MY_HOME。

#!/bin/bash

MY_HOME=/home/ubuntu

cd $MY_HOME

touch $MY_HOME/.ssh/id_rsa
touch $MY_HOME/.ssh/id_rsa.pub
touch $MY_HOME/.ssh/known_hosts

...