linux - 遍历命令并在 bash 中执行

Question

我编写了一个脚本，用于将新 key 传输到我的 AWS 实例。脚本执行时没有错误，但是当我检查实例上的 ~/.ssh/authorized_keys 文件时，我没有看到新的 SSH key 。

这是脚本:

aws_instances=(             
                "ssh -i \"priv.pem\" ubuntu@99.99.99.1" #server1
                "ssh -i \"priv.pem\" ubuntu@99.99.99.2" #server2
                "ssh -i \"priv.pem\" ubuntu@99.99.99.3" #server3
              )
IFS=""
for t in ${aws_instances[@]}; do
  cat ~/newKey.pub | eval $t  'cat >> ~/.ssh/authorized_keys && echo "Key copied"'
done

它确实打印出“ key 已复制”

我已经更改了服务器的 IP 地址。

如果我只执行以下命令，它就可以工作。

cat ~/newKey.pub | ssh -i "priv.pem" ubuntu@99.99.99.1  'cat >> ~/.ssh/authorized_keys && echo "Key copied"'

我的脚本有什么问题？

Answer 1

eval 是代码异味，请像避免害虫一样避免它。

我认为您可以像这样实现完全相同的功能:

#!/usr/bin/env bash

# See: https://tools.ietf.org/html/rfc5737
# 3.  Documentation Address Blocks
#
#   The blocks 192.0.2.0/24 (TEST-NET-1), 198.51.100.0/24 (TEST-NET-2),
#   and 203.0.113.0/24 (TEST-NET-3) are provided for use in
#   documentation.

# Array contains user-name@host-or-ip:ssh-port (ssh-port is optional, default standard 22)
aws_instances=(
  'ubuntu@192.0.2.1'
  'ubuntu@192.0.2.2:2222'
  'ubuntu@192.0.2.3:2022'
)

new_keyfile="${HOME}/newKey.pub"

for instance in "${aws_instances[@]}"; do
  ssh_host="${instance%%:*}" # trim the port if specified
  port="${instance##*:}" # trim the host and keep port if specified
  [[ ${port} == "${instance}" || -z "${port}" ]] && port=22 # use default port

  if ssh-copy-id \
    -i "${new_keyfile}" \
    -p "${port}"
    "${ssh_host}"; then
    printf \
      $"The new key file '%s' has been copied to user@host: '%s', port: %d.\\n" \
      "${new_keyfile}" \
      "${instance}" \
      "${port}"
  else
    printf >&2 \
      $"Could not copy the new key file '%s' to user@host: '%s', port: %d.\\n" \
      "${new_keyfile}" \
      "${instance}" \
      "${port}"
  fi
done