我有一个包含以下行的文件:
<parameter name="PortMappingEnabled" access="readWrite" type="xsd:boolean"></parameter>
<parameter name="PortMappingLeaseDuration" access="readWrite" activeNotify="canDeny" type="xsd:unsignedInt"></parameter>
<parameter name="RemoteHost" access="readWrite"></parameter>
<parameter name="ExternalPort" access="readWrite" type="xsd:unsignedInt"></parameter>
<parameter name="ExternalPortEndRange" access="readWrite" type="xsd:unsignedInt"></parameter>
<parameter name="InternalPort" access="readWrite" type="xsd:unsignedInt"></parameter>
<parameter name="PortMappingProtocol" access="readWrite"></parameter>
<parameter name="InternalClient" access="readWrite"></parameter>
<parameter name="PortMappingDescription" access="readWrite"></parameter>
我想对该文件执行命令以仅提取以下输出中显示的参数名称:
$sedcommand file.txt
PortMappingEnabled
PortMappingLeaseDuration
RemoteHost
ExternalPort
ExternalPortEndRange
InternalPort
PortMappingProtocol
InternalClient
PortMappingDescription
这个命令可能是什么?