云初始化运行命令中的列表与字符串

Question

在official example page 上，云配置描述使用runcmd

#cloud-config

# run commands
# default: none
# runcmd contains a list of either lists or a string
# each item will be executed in order at rc.local like level with
# output to the console
# - runcmd only runs during the first boot
# - if the item is a list, the items will be properly executed as if
#   passed to execve(3) (with the first arg as the command).
# - if the item is a string, it will be simply written to the file and
#   will be interpreted by 'sh'
#
# Note, that the list has to be proper yaml, so you have to quote
# any characters yaml would eat (':' can be problematic)
runcmd:
 - [ ls, -l, / ]
 - [ sh, -xc, "echo $(date) ': hello world!'" ]
 - [ sh, -c, echo "=========hello world'=========" ]
 - ls -l /root
 # Note: Don't write files to /tmp from cloud-init use /run/somedir instead.
 # Early boot environments can race systemd-tmpfiles-clean LP: #1707222.
 - mkdir /run/mydir
 - [ wget, "http://slashdot.org", -O, /run/mydir/index.html ]

现在我的问题是传递命令时列表形式是否与字符串形式有任何不同

这是

[sudo, ufw, --force, enable]

比这更正确？

sudo ufw --force enable

Answer 1

两者都不是更好，但字符串形式会更直接。 runcmd 下的所有内容都被写成脚本，稍后执行。如果它被指定为一个列表，它将被引用，但这应该不是问题。

如果你想看看它是怎么写的，你应该可以在/var/lib/cloud/instance/scripts/runcmd找到生成的脚本。对于您的示例，我看到：

root@me:~# cat /var/lib/cloud/instance/scripts/runcmd 
#!/bin/sh
'ls' '-l' '/'
'sh' '-xc' 'echo $(date) '\'': hello world!'\'''
'sh' '-c' 'echo "=========hello world'\''========="'
ls -l /root
mkdir /run/mydir
'wget' 'http://slashdot.org' '-O' '/run/mydir/index.html'