Get the latest artifact version from Maven Central via shell command

If you need to retrieve the latest version of an artifact on Maven Central you can use the following shell command (example for groupId=org.apache.maven.plugins and artifactId=maven-compiler-plugin):

> curl -s http://search.maven.org/solrsearch/select?q=g:"org.apache.maven.plugins"+AND+a:"maven-compiler-plugin" |grep -Po 'latestVersion.:.\K[^"]*'
> 3.8.0

This will query the search API on search.maven.org for the given groupId and artifactId coordinates. The result from search.maven.org is in JSON format. We are only interested in the value of the ‘latestVersion‘ attribute, which is extracted with grep.

The ‘-s‘ option is for ‘Silent Mode’ to suppress download stats messages from curl and really only print the result from grep. Note that this option is not available on all systems (e.g. macOS).

 

grep command to filter distinct values from XML tags

I have a ton of Oracle Forms XML export files and wanted to know, which different patterns occur for the value of the FormatMask XML attribute. The input looks as follows:

<Item Name="CREATION_DATE" UpdateAllowed="false" DirtyInfo="false" Visible="false" QueryAllowed="false" InsertAllowed="false" Comment="TABLE ALIAS&amp;#10;  FDA&amp;#10;&amp;#10;BASED ON TABLE&amp;#10;  TMI_FINANCIAL_DATA&amp;#10;&amp;#10;COLUMN USAGES&amp;#10;  ...    CREATION_DATE                 SEL&amp;#10;" ParentModule="OBJLIB1" Width="10" Required="false" ColumnName="CREATION_DATE" DataType="Date" ParentModuleType="25" Label="Creation Date" ParentType="15" ParentName="QMSSO$QUERY_ONLY_ITEM" MaximumLength="10" PersistentClientInfoLength="142" ParentFilename="tmiolb65_mla.olb" FormatMask="DD-MM-RRRR">

A naive grep command would print out the whole line, including the file name. After some iterations I came to the following command, which does what I want in a single line.

grep -R -h -o -e FormatMask=\"[^\"]* * | sed 's/FormatMask="//g' | sort | uniq

What the command does is:

• grep recursively (-R) for a regular expression (-e)
• search for FormatMask="<any-char-until-quotation>
• print only the matching part of the line (-o). This will include the prefix FormatMask="
• print without the file name (-h)
• strip off the prefix with sed
• sort the results alphabetically
• remove duplicate lines (uniq)

The result (excerpt)is:

00
09
099
0999
0999999
09999999
0D0
0D999
0D9999
9
90
90D0
90D000
...