How to attach the jenkins build log as part of the email body?

Way 1 –

Put following lines as part of Default Content text box

${BUILD_LOG, maxLines=9999, escapeHtml=false}

this works for free style projects

Way 2 – If you want send only specific line using regex

${BUILD_LOG_REGEX, regex=”\\b(Buildfile|BUILD)\\b”, linesAfter=1}

${BUILD_LOG_REGEX, regex=”^.*?BUILD FAILED.*?$”, linesBefore=0, linesAfter=10, maxMatches=5, showTruncatedLines=false, escapeHtml=true}

${BUILD_LOG_REGEX, regex=”\\b(FC0)\\b”, linesAfter=1}

${BUILD_LOG_REGEX, regex=”^.*?BUILD FAILED.*?$”, linesBefore=0, linesAfter=10, maxMatches=5, showTruncatedLines=false, escapeHtml=true}

${BUILD_LOG_REGEX, regex=”^.*?FC0.*?$”, maxMatches=95, showTruncatedLines=false, escapeHtml=false, matchedLineHtmlStyle=true}

This will show exactly which is expected lines as part of the regEx.

More Info