Unix sed output coming pattern twice in replace

Question

I've an XML file logback-spring.xml.

Now, I want to replace string DEBUG with TRACE, wherever ref="logstash" occurs only in the next line.

The input file looks like below:

  <logger name="com.abcd.tdi" level="DEBUG" additivity="false">
        <appender-ref ref="logstash"/>
        <appender-ref ref="Async-Appender"/>
    </logger>

  <springProfile name="dev">
        <logger name="com.abcd.tdi" level="DEBUG" additivity="false">
            <appender-ref ref="logstash"/>
        </logger>
  <springProfile name="dev">
        <logger name="com.abcd.tdi" level="DEBUG" additivity="false">
            <appender-ref ref="CONSOLE"/>
        </logger>

While using sed command I'm getting output twice in the replacement.

I have used the following sed command:

sed -n -e '/ref="logstash"/!h' -e '/ref="logstash"/{H;x;s/DEBUG/TRACE/}; p; ' logback-spring.xml

Welcome to the site. For clarification, please edit your question to include an example of the current, unwanted output of your command. Also, as a general rule, when working with structured files like XML or JSON, using a dedicated parser (in this case e.g. xmlstarlet) is preferred over using general-purpose text tools like sed or awk. — AdminBee
– AdminBee, Commented Jan 20, 2020 at 12:32

Kusalananda · Accepted Answer · 2020-01-20 13:11:37Z

Given a well-formed XML document, like the following (modified from your example):

<?xml version="1.0"?>
<root>
  <springProfile name="dev">
    <logger name="com.abcd.tdi" level="DEBUG" additivity="false">
      <appender-ref ref="logstash"/>
      <appender-ref ref="Async-Appender"/>
    </logger>
  </springProfile>
  <springProfile name="dev">
    <logger name="com.abcd.tdi" level="DEBUG" additivity="false">
      <appender-ref ref="logstash"/>
    </logger>
  </springProfile>
  <springProfile name="dev">
    <logger name="com.abcd.tdi" level="DEBUG" additivity="false">
      <appender-ref ref="CONSOLE"/>
    </logger>
  </springProfile>
</root>

you may use xmlstarlet to change all level attributes that are set to DEBUG to TRACE for each logger node whose appender-ref child node has a ref attribute that is logstash, like so:

$ xmlstarlet ed -u '//logger[appender-ref/@ref = "logstash"]/@level[. = "DEBUG"]' -v 'TRACE' file.xml
<?xml version="1.0"?>
<root>
  <springProfile name="dev">
    <logger name="com.abcd.tdi" level="TRACE" additivity="false">
      <appender-ref ref="logstash"/>
      <appender-ref ref="Async-Appender"/>
    </logger>
  </springProfile>
  <springProfile name="dev">
    <logger name="com.abcd.tdi" level="TRACE" additivity="false">
      <appender-ref ref="logstash"/>
    </logger>
  </springProfile>
  <springProfile name="dev">
    <logger name="com.abcd.tdi" level="DEBUG" additivity="false">
      <appender-ref ref="CONSOLE"/>
    </logger>
  </springProfile>
</root>

An XPath query similar to what choroba is using would also work:

xmlstarlet ed -u '//logger[@level = "DEBUG"][appender-ref/@ref = "logstash"]/@level' -v 'TRACE' file.xml

choroba · Accepted Answer · 2020-01-20 12:47:55Z

0

Use an XML-aware tool when working with XML. For example, in xsh, a wrapper around XML::LibXML, you can achieve the result by

open logback-spring.xml ;
for //logger[@level='DEBUG'][appender-ref/@ref='logstash']
    set @level 'TRACE' ;
save :b ;

If your XML contains namespace declarations, the code will be a bit more complex.

edited Jan 20, 2020 at 12:47

answered Jan 20, 2020 at 12:37

choroba

49.7k7 gold badges92 silver badges119 bronze badges

Add a comment |

Stack Exchange Network

Unix sed output coming pattern twice in replace

2 Answers 2

You must log in to answer this question.

Hot Network Questions

Unix sed output coming pattern twice in replace

2 Answers 2

You must log in to answer this question.

Related

Hot Network Questions