Question

我需要创建一个脚本，在文件（XML）中的特定行之后添加文本。以下是我到目前为止的情况：

echo
echo "This script will blah blah blah"
echo
read -p "Press Enter to continue..."
clear

var1=`grep -n "<string>" <file> | awk -F ":" '{print $1}'` //var1 = line number

function EnterID()
{
echo -n "Enter ID: "
read ID
var2="text to be added"
sed "$((var1+1))i$var2" <file> > <file> //add text to file, overwrite file
#var1="$((var1+1))" //increment line number???
echo
echo "ID successfully added to file"
echo
EnterNewID
}

EnterNewID()
{
read -p "Press Enter to continue..."
clear
echo -n "Would you like to add another ID? (y)es or (n)o: "
read answer
clear

if [ $answer = "y" ]; then
    EnterID
else
    exit
fi
}

EnterID

该脚本第一次工作。但是，如果用户尝试添加其他ID，则会覆盖第一个ID。我还应该声明我不是程序员（更像是网络人员）。我有一点脚本编写经验，但这都是。

其他信息：

原件：

<SubscriberXML>
  <Subscribers> 
    <Subscriber address="0.0.0.0" id="1" />
    <Subscriber address="0.0.0.0" id="2" />
    <Subscriber address="0.0.0.0" id="3" />
    <Subscriber address="0.0.0.0" id="4" />
    <Subscriber address="0.0.0.0" id="5" />
  </Subscribers>
</SubscriberXML>

初次使用后：

<SubscriberXML>
  <Subscribers> 
    <Subscriber address="0.0.0.0" id="X" /> // newly added ID
    <Subscriber address="0.0.0.0" id="1" />
    <Subscriber address="0.0.0.0" id="2" />
    <Subscriber address="0.0.0.0" id="3" />
    <Subscriber address="0.0.0.0" id="4" />
    <Subscriber address="0.0.0.0" id="5" />
  </Subscribers>
</SubscriberXML>

第二次使用后：

<SubscriberXML>
  <Subscribers> 
    <Subscriber address="0.0.0.0" id="Y" /> // newly added ID
    <Subscriber address="0.0.0.0" id="1" />
    <Subscriber address="0.0.0.0" id="2" />
    <Subscriber address="0.0.0.0" id="3" />
    <Subscriber address="0.0.0.0" id="4" />
    <Subscriber address="0.0.0.0" id="5" />
  </Subscribers>
</SubscriberXML>

想要：

<SubscriberXML>
  <Subscribers> 
    <Subscriber address="0.0.0.0" id="Y" />
    <Subscriber address="0.0.0.0" id="X" />
    <Subscriber address="0.0.0.0" id="1" />
    <Subscriber address="0.0.0.0" id="2" />
    <Subscriber address="0.0.0.0" id="3" />
    <Subscriber address="0.0.0.0" id="4" />
    <Subscriber address="0.0.0.0" id="5" />
  </Subscribers>
</SubscriberXML>

Answer 1

你不能这样做：

any_command file > file

shell将处理重定向 first ，并且在 shell启动命令之前文件将被截断。您现在正在将空文件传递给命令。

有几种技巧：

如果命令成功完成，则使用临时文件并覆盖原始文件

temp=$(mktemp) any_command file > "$temp" && mv "$temp" file

安装moreutils包并使用sponge命令

any_command file | sponge file

Answer 2

如果您刚刚收集了所有添加内容，那么程序和问题就会简单得多，然后进行一次替换。

nl='
'
replace="i\\$nl"
while read -p "What should be added? (Empty input to finish) " entry; do
    if [ "$entry" = "" ]; then
        break
    fi
    replace="$replace$nl$entry"
done
sed -i "/<string>/$replace" file

将文本添加到特定行linux脚本

2 个答案: