I am using pdf chain to merge several single page pdf documents. But this program only adds 26 pages at a time, I want to combine 100 pages at once. I am doing something wrong or is there a setting I am missing?
It seems you are using a very old version of PDF Chain. Newer versions don't have this limitation. There is a PPA with the actual version of pdfchain and the fitting version of pdftk:
Seems you want to remove single pages from a document. Don't use burst and cat for this. Use cat only! For example do the page selection "1-3 5-end" for removing page 4. Read the documentation of pdftk and pdfchain about: