This is a small gawk script to put all the pages= page ranges in a .bib file into a uniform format, either 1234-1256 or upon request 1234-56; null ranges such as 1234-1234 are always scrunched to just 1234. The script squeezes out spaces around the separator; can make all separators one- or two-hyphens upon request. The script is very conservative: it is probably impossible for it actually to mess up a file.