D.9.6.4 Splitting a File Manually

You should split a large file or else let the texinfo-format-buffer or makeinfo-buffer command do it for you automatically. (Generally you will let one of the formatting commands do this job for you. See Creating an Info File.)

The split-off files are called the indirect subfiles.

Info files are split to save memory. With smaller files, Emacs does not have to make such a large buffer to hold the information.

If an Info file has more than 30 nodes, you should also make a tag table for it. See Using Info-validate, for information about creating a tag table. (Again, tag tables are usually created automatically by the formatting command; you only need to create a tag table yourself if you are doing the job manually. Most likely, you will do this for a large, unsplit file on which you have run Info-validate.)

Visit the Info file you wish to tagify and split and type the two commands:

M-x Info-tagify
M-x Info-split

(Note that the ‘I’ in ‘Info’ is uppercase.)

When you use the Info-split command, the buffer is modified into a (small) Info file which lists the indirect subfiles. This file should be saved in place of the original visited file. The indirect subfiles are written in the same directory the original file is in, with names generated by appending ‘-’ and a number to the original file name.

The primary file still functions as an Info file, but it contains just the tag table and a directory of subfiles.