[Google Cloud][Compute Engine] 在启动脚本中找不到 Linux 基础命令

Question

我在为实例组运行虚拟机启动脚本时遇到问题。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

您在脚本中修改了 PATH 环境：

PATH=/home/ubuntu

但是，PATH 是 bash 的一个 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''.

因此几乎所有命令都找不到。 （除非它们在 /home/ubuntu 下）

---

如果你只是想设置一个变量作为用户文件夹来操作脚本，请将变量名改为像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

...

Answer 2

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，因为相应的可执行文件用于运行这些命令在您刚刚设置的新路径 /home/ubuntu 上不可用。您可以通过将该变量重命名为 PATH 以外的任何名称以及它在脚本中出现的所有名称来解决此问题。您也可以使用小写的相同变量名称。 （比如path=home/ubuntu）。

PATH 环境变量是一个以冒号分隔的目录列表，当您输入命令时，shell 会搜索这些目录。程序文件（可执行文件）保存在 Unix 系统上的许多不同位置。当您请求特定程序时，您的路径会告诉 Unix shell 在系统上的哪个位置。