Here is a quicky to use wget to log in to jspwiki and force a re-indexing of pages:
# POST to log in and get login and session cookies
wget --verbose --save-cookies=cookie --keep-session-cookies --post-data="j_username=myuid&j_password=mypw&redirect=Main&submitlogin=Login" "http://wiki.mydomain.com/JSPWiki/Login.jsp" --output-document "MainPostLogin.html"
# POST to kick off reindexing using cookies
wget --verbose --load-cookies=cookie --post-data="tab-admin=core&tab-core=Search+manager&bean=com.ecyrd.jspwiki.ui.admin.beans.SearchManagerBean&searchmanagerbean-reload=Force+index+reload" --output-document "PostFromForceIndexReload.html" "http://wiki.mydomain.com/JSPWiki/admin/Admin.jsp"
Tweak myuid, mypw, and wiki.mydomain.com in the above to have them be what you need. Drop the output once you're comfortable it's working (I was saving it in the above to make sure I could see artifacts of being authenticated in the output).
Put the above into a cron'ed script and run it hourly.
Note that all versions of wget are not created equal as 1.10 didn't seem to work but 1.10.2 and 1.12 worked fine for the above.