The \include command is used in conjunction with the \includeonly command for selective inclusion of files. The file argument is the first name of a file, denoting FILE.TEX. If file is one the file names in the file list of the \includeonly command or if there is no \includeonly command, the \include command is equivalent to

\clearpage \input{file} \clearpage

except that if the file FILE.TEX does not exist, then a warning message rather than an error is produced. If the file is not in the file list, the \include command is equivalent to \clearpage.

The \include command may not appear in the preamble or in a file read by another \include command.