Bash 在sed命令语法中调用变量

我正在创建一个脚本，使我的组织能够更轻松地将工作站添加到Nagios监控系统中

每次脚本运行时，我都希望能够输入主机名、别名和地址（作为用户输入的变量），并在sed命令中调用这些变量，以便“创建”一个新主机比键入所有内容快得多

我试图在sed找到后添加整个字符串 “主机的地址}”

我假设是/a（在找到所述字符串后追加） 尽管如此，使用双引号仍然不允许调用变量

#!bin/bash

# Prompt for hostname, alias, and IP address of new host
# take user input has variable to be used in sed 

# Takes user input for hostname
echo host_name : 
read var_hostname    
# Takes user input for alias
echo alias : 
read var_alias
# Takes user input for ip address
echo address : 
read var_address
# searches for the top-most instance "address of the host" within the     windows.cfg file
# after said instance is found, appends the new string below, which calls     for the variables received 
# previously by user
sed -i -e  " address of the host } /a 
define host{
    use             windows-server  ; Inherit default values from a     template
    host_name       $var_hostname       ; The name we are giving to this     host
    alias           $var_alias       ; A longer name associated with the host
    address         $var_address     ; IP address of the host
    }" 
    windows.cfg        

---

我希望字符串“define host{}”与用户输入的变量一起写入文件。改为修改windows.cfg的文件

 cat windows.cfg 
#some settings
#more settings
test
abc

lot of stuff

test2

backup

 address of the host }

Sed脚本：

 cat sed.sh 
#!/bin/bash

# Prompt for hostname, alias, and IP address of new host
# take user input has variable to be used in sed

# Takes user input for hostname
echo host_name :
read var_hostname
# Takes user input for alias
echo alias :
read var_alias
# Takes user input for ip address
echo address :
read var_address
# searches for the top-most instance "address of the host" within the     windows.cfg file
# after said instance is found, appends the new string below, which calls     for the variables received
# previously by user
sed -e  '/address of the host }/r'<(
echo "define host{"
echo "   use             windows-server  ; Inherit default values from a template"
echo "   host_name       $var_hostname       ; The name we are giving to this host"
echo "   alias           $var_alias       ; A longer name associated with the host"
echo "   address         $var_address     ; IP address of the host"
echo "   }") -i -- windows.cfg

输出：

 ./sed.sh 
host_name :
allan.com
alias :
allan
address :
123.123.123.123

 cat windows.cfg 
#some settings
#more settings
test
abc

lot of stuff

test2

backup

 address of the host }
define host{
   use             windows-server  ; Inherit default values from a template
   host_name       allan.com       ; The name we are giving to this host
   alias           allan       ; A longer name associated with the host
   address         123.123.123.123     ; IP address of the host
   }

解释：

 ./sed.sh 
host_name :
allan.com
alias :
allan
address :
123.123.123.123

 cat windows.cfg 
#some settings
#more settings
test
abc

lot of stuff

test2

backup

 address of the host }
define host{
   use             windows-server  ; Inherit default values from a template
   host_name       allan.com       ; The name we are giving to this host
   alias           allan       ; A longer name associated with the host
   address         123.123.123.123     ; IP address of the host
   }

---

我决定在

sed

中使用

r

命令（读取文件内容以插入文件），而不是使用

a

。然后我使用符号

变量总是在双引号内被替换，我看不出为什么它在这里不起作用。如果用文字字符串替换变量，是否有效？
主机地址}a
应该是
/host地址/a
我尝试使用/option/但这否定了变量。现在正在调用变量…但我在运行脚本时收到了这个消息：expression#1，char 28:commands后面的额外字符如果您想查看shell脚本正在做什么，请将set-x放到开头。然后它将显示所有正在执行的命令，并填入变量。@Allan是的，您的解释写得非常好，有助于澄清分配。我还按照建议执行了-x命令，以查看该命令实际上也在做什么，这很有用。脚本运行时没有错误…但windows.cfg文件没有更改。