iRule to remove any first two segments from the URI

when HTTP_REQUEST {
 set uri [HTTP::uri]
 set skip_path_length [expr { 1 + [string length [lrange [split $uri "/"] 1 2]] }]
 HTTP::uri "[string range [HTTP::uri] $skip_path_length end]"
}

OR:

when HTTP_REQUEST {
 set uri [HTTP::uri]
 HTTP::uri "/[join [lrange [split $uri "/"] 3 end] "/"]"
}

tcl test example:

(bin) 79 % set uri /path/to/file.xhtml
/path/to/file.xhtml
(bin) 80 % string range $uri [expr { 1 + [string length [lrange [split $uri "/"] 1 2]] }] end
/file.xhtml
(bin) 81 %puts "/[join [lrange [split $uri "/"] 3 end] "/"]"
/file.xhtml

hi RoadRunnerA, if xuwen's answer was helpful, would you mind accepting the solution? This helps everyone knowing that a solution was reached for the problem being discussed.