An arbitrary number of input files can be specified. Input files can be specified in two ways. The command line option -i is immediately followed by a file name.

bibtool -i input_file

The resource name input can be used to specify additional input files.

input = {input_file}

Input files are processed in the order they are given. If no input file is specified the standard input is used to read from.

Depending on the special configuration of BibTool there are two ways of searching for BibTeX files. The native mode of BibTool uses a list of directories and a list of extensions to find a file. Alternatively the kpathsea library can be used which provides additional features like the recursive searching in subdirectories. First we look at the native BibTool searching mechanism.

The files are searched in the following way. If the file is can't be opened as given the extension .bib is appended and another read is tried. In addition directories can be given which are searched for input files. The search path can be given in two different ways. First, the resource name bibtex.search.path can be set to contain a search path specification.

bibtex.search.path = {directory1:directory2:directory3}

The elements of the search path are separated by colons. Thus colons are not allowed as parts of directories. Another source of the search path is the environment variable BIBINPUTS. This environment variable is usually used by BibTeX to specify the search path. The syntax of the specification is the same as for the resource bibtex.search.path. To check the appropriate way to set your environment variable consult the documentation of your shell, since this is highly dependent on it.

To allow adaption to operating systems other than UN*X the following resources can be used. The name of the environment bibtex.env.name overwrites the name of the environment variable which defaults to BIBINPUTS.

bibtex.env.name = {ENVIRONMENT_VARIABLE}

The first character of the resource env.separator is used as separator of directories in the resource bibtex.search.path and the environment variable given as bibtex.env.name.

env.separator = {:}

The default character separating directories in a file name is the slash (/). The first character of the resource dir.file.separator can be used to change this value.

dir.file.separator = {\}

Note that the defaults for env.separator and dir.file.separator are set at compile time to a value suitable for the operating system. Usually you don't have to change them at all. E.g. for MSD*S machines the env.separator is usually set to ; and the dir.file.separator is usually set to \.

If the kpathsea library is used for searching BibTeX files then some of the resources described above have no effect. They are replaced by their kpathsea counterparts. Most probably you are using the kpathsea library already in other TeX related programs. Thus I just have to direct you to the documentation distributed with the kpathsea library for details.