var cat = [ "Line-based", "Nth Line" ];
var titles = [
[   [ "Get the 4th line of a file.","p.20000929b" ]],
[   [ "Get the 3rd through 6th lines of a file.","p.20000929c" ],
   [ "Delete the 3rd through 6th lines of a file.","p.20000929f" ],
   [ "Get the last 6 lines of a file.","p.20060714a" ],
   [ "Delete the last 6 lines of a file.","p.20000929g" ],
   [ "Delete the last 8th through 4th lines of a file.","p.20001206a" ]],
[   [ "Get every Nth line of a file. ","p.20090515a" ],
   [ "Append a line after every <i>N</i>th (for example, 4th) line.","p.20010222a" ],
   [ "Delete every 4th line (e.g., 4th, 8th, 12th, ...) of a file.","p.20060222a" ]],
[   [ "Join every <i>N</i> lines to one.","p.20090915a" ]],
[   [ "For each line of a file, append the previous line to the end of it.","p.20041014a" ],
   [ "For each line of a file, append the next line to the end of it.","p.20050128a" ]]];
var subcat = [ "Single Line", "From <i>N</i>th to <i>M</i>th Lines", "Every <i>N</i>th Line of a File", "Every <i>N</i> Lines of a File", "Every Line" ];