BIBCLEAN 1 "15 January 1993" "Version 2.06.24"

Table of contents


bibclean - prettyprint and syntax check BibTeX and Scribe bibliography data base files


bibclean [ -author ] [ -error-log filename ] [ -help ] [ '-?' ] [ -init-file filename ] [ -max-width nnn ] [ -[no-]check-values ] [ -[no-]delete-empty-values ] [ -[no-]file-position ] [ -[no-]fix-font-changes ] [ -[no-]fix-initials ] [ -[no-]fix-names ] [ -[no-]par-breaks ] [ -[no-]prettyprint ] [ -[no-]print-patterns ] [ -[no-]read-init-files ] [ -[no-]remove-OPT-prefixes ] [ -[no-]scribe ] [ -[no-]trace-file-opening ] [ -[no-]warnings ] [ -version ] <infile or bibfile1 bibfile2 bibfile3 ... >outfile

All options can be abbreviated to a unique leading prefix.

An explicit file name of ``-'' represents standard input; it is assumed if no input files are specified.

On VAX VMS and IBM PC DOS, the leading ``-'' on option names may be replaced by a slash, ``/''; however, the ``-'' option prefix is always recognized.


bibclean prettyprints input BibTeX files to stdout, and checks the brace balance and bibliography entry syntax as well. It can be used to detect problems in BibTeX files that sometimes confuse even BibTeX itself, and importantly, can be used to normalize the appearance of collections of BibTeX files.

Here is a summary of the formatting actions:

The standardized format of the output of bibclean facilitates the later application of simple filters, such as bibextract(1), bibindex(1), biblook(1), bibsort(1), citefind(1), and citetags(1), to process the text, and also is the one expected by the GNU Emacs BibTeX support functions.


Command-line switches may be abbreviated to a unique leading prefix, and letter case is not significant. All options are parsed before any input bibliography files are read, no matter what their order on the command line. Options that correspond to a yes/no setting of a flag have a form with a prefix "no-" to set the flag to no. For such options, the last setting determines the flag value used. This is significant when options are also specified in initialization files (see the INITIALIZATION FILES manual section).
Display an author credit on the standard error unit, stderr. Sometimes an executable program is separated from its documentation and source code; this option provides a way to recover from that.
-error-log filename
Redirect stderr to the indicated file, which will then contain all of the error and warning messages. This option is provided for those systems that have difficulty redirecting stderr.
-help or -?
Display a help message on stderr, giving a usage description, similar to this section of the manual pages.
-init-file filename
Provide an explicit value pattern initialization file. It will be processed after any system-wide and job-wide initialization files found on the PATH (for VAX VMS, SYS$SYSTEM) and BIBINPUTS search paths, respectively, and may override them. It in turn may be overridden by a subsequent file-specific initialization file. The initialization file name can be changed at compile time, or at run time through a setting of the environment variable BIBCLEANINI, but defaults to .bibcleanrc on UNIX, and to bibclean.ini elsewhere. For further details, see the INITIALIZATION FILES manual section.
-max-width nnn
bibclean normally limits output line widths to 72 characters, and in the interests of consistency, that value should not be changed. Occasionally, special-purpose applications may require different maximum line widths, so this option provides that capability. The number following the option name can be specified in decimal, octal (starting with 0), or hexadecimal (starting with 0x). A zero or negative value is interpreted to mean unlimited, so -max-width 0 can be used to ensure that each field/value pair appears on a single line.

When -no-prettyprint requests bibclean to act as a lexical analyzer, the default line width is unlimited, unless overridden by this option.

When bibclean is prettyprinting, line wrapping will be done only at a space. Consequently, a long non-blank character sequence may result in the output exceeding the requested line width.

When bibclean is lexing, line wrapping is done by inserting a backslash-newline pair when the specified maximum is reached, so no line length will ever exceed the maximum.

With the positive form, apply heuristic pattern matching to field values in order to detect possible errors (e.g. ``year = "192"'' instead of ``year = "1992"''), and issue warnings when unexpected patterns are found.

This checking is usually beneficial, but if it produces too many bogus warnings for a particular bibliography file, you can disable it with the negative form of this option. Default: yes.

With the positive form, remove all field/value pairs for which the value is an empty string. This is helpful in cleaning up bibliographies generated from text editor templates. Compare this option with -[no-]remove-OPT-prefixes described below. Default: no.
With the positive form, give detailed file position information in warning and error messages. Default: no.
With the positive form, supply an additional brace level around font changes in titles to protect against downcasing by some BibTeX styles. Font changes that already have more than one level of braces are not modified.

For example, if a title contains the Latin phrase {\em Dictyostelium Discoideum} or {\em {D}ictyostelium {D}iscoideum}, then downcasing will incorrectly convert the phrase to lower-case letters. Most BibTeX users are surprised that bracing the initial letters does not prevent the downcase action. The correct coding is {{\em Dictyostelium Discoideum}}. However, there are also legitimate cases where an extra level of bracing wrongly protects from downcasing. Consequently, bibclean will normally not supply an extra level of braces, but if you have a bibliography where the extra braces are routinely missing, you can use this option to supply them.

If you think that you need this option, it is strongly recommended that you apply bibclean to your bibliography file with and without -fix-font-changes, then compare the two output files to ensure that extra braces are not being supplied in titles where they should not be present. You will have to decide which of the two output files is the better choice, then repair the incorrect title bracing by hand.

Since font changes in titles are uncommon, except for cases of the type which this option is designed to correct, it should do more good than harm. Default: no.

With the positive form, insert a space after a period following author initials. Default: yes.
With the positive form, reorder author and editor name lists to remove commas at brace level zero, placing first names or initials before last names. Default: yes.
With the negative form, a paragraph break (either a formfeed, or a line containing only spaces) is not permitted in value strings, or between field/value pairs. This may be useful to quickly trap runaway strings arising from mismatched delimiters. Default: yes.
Normally, bibclean functions as a prettyprinter. However, with the negative form of this option, it acts as a lexical analyzer instead, producing a stream of lexical tokens. See the LEXICAL ANALYSIS manual section for further details. Default: yes.
With the positive form, print the value patterns read from initialization files as they are added to internal tables. Use this option to check newly-added patterns, or to see what patterns are being used.

When bibclean is compiled with native pattern-matching code (the default), these patterns are the ones that will be used in checking value strings for valid syntax, and all of them are specified in initialization files, rather than hard-coded into the program. For further details, see the INITIALIZATION FILES manual section. Default: no.

With the negative form, suppress loading of system-, user-, and file-specific initialization files. Initializations will come only from those files explicitly given by -init-file filename options. Default: yes.
With the positive form, remove the ``OPT'' prefix from each field name where the corresponding value is not an empty string. The prefix ``OPT'' must be entirely in upper-case to be recognized.

This option is for bibliographies generated with the help of the GNU Emacs BibTeX editing support, which generates templates with optional fields identified by the ``OPT'' prefix. Although the function M-x normally bound to the keystrokes C-c does the job, users often forget, with the result that BibTeX does not recognize the field name, and ignores the value string. Compare this option with -[no-]delete-empty-values described above. Default: no.

With the positive form, accept input syntax conforming to the Scribe document system. The output will be converted to conform to BibTeX syntax. See the SCRIBE BIBLIOGRAPHY FORMAT manual section for further details. Default: no.
With the positive form, record in the error log file the names of all files which bibclean attempts to open. Use this option to identify where initialization files are located. Default: no.
With the positive form, allow all warning messages. The negative form is not recommended since it may mask problems that should be repaired. Default: yes.
Display the program version number on stderr. This will also include an indication of who compiled the program, the host name on which it was compiled, the time of compilation, and the type of string-value matching code selected, when that information is available to the compiler.


When bibclean detects an error, it issues an error message to both stderr and stdout. That way, the user is clearly notified, and the output bibliography also contains the message at the point of error.

Error messages begin with a distinctive pair of queries, ??, beginning in column 1, followed by the input file name and line number. If the -file-position option was specified, they also contain the input and output positions of the current file, entry, and value. Each position includes the file byte number, the line number, and the column number. In the event of a runaway string argument, the entry and value positions should precisely pinpoint the erroneous bibliography entry, and the file positions will indicate where it was detected, which may be rather later in the files.

Warning messages identify possible problems, and are therefore sent only to stderr, and not to stdout, so they never appear in the output file. They are identified by a distinctive pair of percents, %%, beginning in column 1, and as with error messages, may be followed by file position messages if the -file-position option was specified.

For convenience, the first line of each error and warning message sent to stderr is formatted according to the expectations of the GNU Emacs next-error command. You can invoke bibclean with the Emacs M-x compile<RET>bibclean filename.bib > command, then use the next-error command, normally bound to C-x ` (that's a grave, or back, accent), to move to the location of the error in the input file.

If error messages are ignored, and left in the output bibliography file, they will precipitate an error when the bibliography is next processed with BibTeX.

After issuing an error message, bibclean then resynchronizes its input by copying it verbatim to stdout until a new bibliography entry is recognized on a line in which the first non-blank character is an at-sign (@). This ensures that nothing is lost from the input file(s), allowing corrections to be made in either the input or the output files. However, if bibclean detects an internal error in its data structures, it will terminate abruptly without further input or output processing; this kind of error should never happen, and if it does, it should be reported immediately to the author of the program. Errors in initialization files, and running out of dynamic memory, will also immediately terminate bibclean.


bibclean can be compiled with one of three different types of pattern matching; the choice is made by the installer at compile time:

The second and third versions are the ones of most interest here, because they allow the user to control what values are considered acceptable. However, command-line options can also be specified in initialization files, no matter which pattern matching choice was selected.

When bibclean starts, it searches for initialization files, finding the first one in the system executable program search path (on UNIX and IBM PC DOS, PATH) and the first one in the BIBINPUTS search path, and processes them in turn. Then, when command-line arguments are processed, any additional files specified by -init-filefilename options are also processed. Finally, immediately before each named bibliography file is processed, an attempt is made to process an initialization file with the same name, but with the extension changed to .ini. The default extension can be changed by a setting of the environment variable BIBCLEANEXT. This scheme permits system-wide, user-wide, session-wide, and file-specific initialization files to be supported.

When input is taken from stdin, there is no file-specific initialization.

For precise control, the -no-init-files option suppresses all initialization files except those explicitly named by -init-filefilename options, either on the command line, or in requested initialization files.

Recursive execution of initialization files with nested -init-file options is permitted; if the recursion is circular, bibclean will finally get a non-fatal initialization file open failure after opening too many files. This terminates further initialization file processing. As the recursion unwinds, the files are all closed, then execution proceeds normally.

An initialization file may contain empty lines, comments from percent to end of line (just like TeX), option switches, and field/pattern or field/pattern/message assignments. Leading and trailing spaces are ignored. This is best illustrated by a short example:

% This is a small bibclean initialization file

-init-file /u/math/bib/.bibcleanrc %% departmental patterns

chapter = "\"D\""                 %% 23

pages   = "\"D--D\""              %% 23--27

volume  = "\"D \an\d D\""       %% 11 and 12

year    = \
   "\"dddd, dddd, dddd\"" \
   "Multiple years specified."      %% 1989, 1990, 1991

-no-fix-names   %% do not modify author/editor lists

Long logical lines can be split into multiple physical lines by breaking at a backslash-newline pair; the backslash-newline pair is discarded. This processing happens while characters are being read, before any further interpretation of the input stream.

Each logical line must contain a complete option (and its value, if any), or a complete field/pattern pair, or a field/pattern/message triple.

Comments are stripped during the parsing of the field, pattern, and message values. The comment start symbol is not recognized inside quoted strings, so it can be freely used in such strings.

Comments on logical lines that were input as multiple physical lines via the backslash-newline convention must appear on the last physical line; otherwise, the remaining physical lines will become part of the comment.

Pattern strings must be enclosed in quotation marks; within such strings, a backslash starts an escape mechanism that is commonly used in UNIX software. The recognized escape sequences are:

alarm bell (octal 007)
backspace (octal 010)
formfeed (octal 014)
newline (octal 012)
carriage return (octal 015)
horizontal tab (octal 011)
vertical tab (octal 013)
character number octal ooo (e.g  12 is linefeed). Up to 3 octal digits may be used.
character number hexadecimal hh (e.g.  x0a is linefeed). xhh may be in either letter case. Any number of hexadecimal digits may be used.

Backslash followed by any other character produces just that character. Thus, \% gets a literal percent into a string (preventing its interpretation as a comment), \" produces a quotation mark, and \ produces a single backslash.

An ASCII NUL ( ) in a string will terminate it; this is a feature of the C programming language in which bibclean is implemented.

Field/pattern pairs can be separated by arbitrary space, and optionally, either an equals sign or colon functioning as an assignment operator. Thus, the following are equivalent:

pages "\"D--D\""
  pages = "\"D--D\""
  pages : "\"D--D\""
pages   "\"D--D\""

Each field name can have an arbitrary number of patterns associated with it; however, they must be specified in separate field/pattern assignments.

An empty pattern string causes previously-loaded patterns for that field name to be forgotten. This feature permits an initialization file to completely discard patterns from earlier initialization files.

Patterns for value strings are represented in a tiny special-purpose language that is both convenient and suitable for bibliography value-string syntax checking. While not as powerful as the language of regular-expression patterns, its parsing can be portably implemented in less than 3% of the code in a widely-used regular-expression parser (the GNU regexp package).

The patterns are represented by the following special characters:

one or more spaces
exactly one letter
one or more letters
exactly one digit
one or more digits
exactly one Roman numeral
one or more Roman numerals (i.e. a Roman number)
exactly one word (one or more letters and digits)
one or more space-separated words, beginning and ending with a word
one `special' character, one of the characters <space>!#()*+,-./:;?[]~, a subset of punctuation characters that are typically used in string values
one or more `special' characters
one or more `special'-separated words, beginning and ending with a word
exactly one x (x is any character), possibly with an escape sequence interpretation given earlier
exactly the character x (x is anything but one of these pattern characters: aAdDrRwW.:<space>\)

The X pattern character is very powerful, but generally inadvisable, since it will match almost anything likely to be found in a BibTeX value string. The reason for providing pattern matching on the value strings is to uncover possible errors, not mask them.

There is no provision for specifying ranges or repetitions of characters, but this can usually be done with separate patterns. It is a good idea to accompany the pattern with a comment showing the kind of thing it is expected to match. Here is a portion of an initialization file giving a few of the patterns used to match number value strings:

number  =       "\"D\""         %% 23
number  =       "\"A AD\""      %% PN LPS5001
number  =       "\"A D(D)\""    %% RJ 34(49)
number  =       "\"A D\""       %% XNSS 288811
number  =       "\"A D\.D\""   %% Version 3.20
number  =       "\"A-A-D-D\""   %% UMIAC-TR-89-11
number  =       "\"A-A-D\""     %% CS-TR-2189
number  =       "\"A-A-D\.D\"" %% CS-TR-21.7

For a bibliography that contains only article entries, this list should probably be reduced to just the first pattern, so that anything other than a digit string fails the pattern-match test. This is easily done by keeping bibliography-specific patterns in a corresponding file with extension .ini, since that file is read automatically.

You should be sure to use empty pattern strings in this pattern file to discard patterns from earlier initialization files.

The value strings passed to the pattern matcher contain surrounding quotes, so the patterns should also. However, you could use a pattern specification like "\"D" to match an initial digit string followed by anything else; the omission of the final quotation mark \" in the pattern allows the match to succeed without checking that the next character in the value string is a quotation mark.

Because the value strings are intended to be processed by TeX, the pattern matching ignores braces, and TeX control sequences, together with any space following those control sequences. Spaces around braces are preserved. This convention allows the pattern fragment A-AD-D to match the value string TN-K\slash27-70, because the value is implicitly collapsed to TN-K27-70 during the matching operation.

bibclean's normal action when a string value fails to match any of the corresponding patterns is to issue a warning message something like this: "Unexpected value in ``year = "192"''. In most cases, that is sufficient to alert the user to a problem. In some cases, however, it may be desirable to associate a different message with a particular pattern. This can be done by supplying a message string following the pattern string. Format items %% (single percent), %e (entry name), %f (field name), %k (citation key), and %v (string value) are available to get current values expanded in the messages. Here is an example:

chapter = "\"D:D\"" "Colon found in ``%f = %v''" %% 23:2

To be consistent with other messages output by bibclean, the message string should not end with punctuation.

If you wish to make the message an error, rather than just a warning, begin it with a query (?), like this:

chapter = "\"D:D\"" "?Colon found in ``%f = %v''" %% 23:2

The query will not be included in the output message.

Escape sequences are supported in message strings, just as they are in pattern strings. You can use this to advantage for fancy things, such as terminal display mode control. If you rewrite the previous example as

chapter = "\"D:D\"" \
          "? 33[7mColon found in ``%f = %v'' 33[0m" %% 23:2

the error message will appear in inverse video on display screens that support ANSI terminal control sequences. Such practice is not normally recommended, since it may have undesirable effects on some output devices. Nevertheless, you may find it useful for restricted applications.

For some types of bibliography fields, bibclean contains special-purpose code to supplement or replace the pattern matching:

Values for other fields are checked only against patterns. You can provide patterns for any field you like, even ones bibclean does not already know about. New ones are simply added to an internal table that is searched for each string to be validated.

The special field, key, represents the bibliographic citation key. It can be given patterns, like any other field. Here is an initialization file pattern assignment that will match an author name, a colon, an alphabetic string, and a two-digit year:

key = "A:Add"                     %% Knuth:TB86

Notice that no quotation marks are included in the pattern, because the citation keys are not quoted. You can use such patterns to help enforce uniform naming conventions for citation keys, which is increasingly important as your bibliography data base grows.


When -no-prettyprint is specified, bibclean acts as a lexical analyzer instead of a prettyprinter, producing output in lines of the form


Each output line contains a single complete token, identified by a small integer number for use by a computer program, a token type name for human readers, and a string value in quotes.

Special characters in the token value string are represented with ANSI/ISO Standard C escape sequences, so all characters other than NUL are representable, and multi-line values can be represented in a single line.

Here are the token numbers and token type names that can appear in the output when -prettyprint is specified:

 2   AT
 3   COMMA
 5   ENTRY
 7   FIELD
10   KEY
16   SHARP
17   SPACE
19   VALUE

Programs that parse such output should also be prepared for lines beginning with the warning prefix, %%, or the error prefix, ??, and for ANSI/ISO Standard C line number directives of the form

# line 273 "texbook1.bib"
which record the line number and file name of the current input file.

If a -max-width nnn command-line option was specified, long output lines will be wrapped at a backslash-newline pair, and consequently, software that processes the lexical token stream should be prepared to collapse such wrapped lines back into single lines.

As an example of the use of -no-prettyprint, the UNIX command pipeline

bibclean -no-prettyprint mylib.bib | \
    awk '$2 == "KEY" {print $3}' | \
    sed -e 's/"//g' | \
will extract a sorted list of all citation keys in the file mylib.bib.

A certain amount of processing will have been done on the tokens. In particular, delimiters equivalent to braces will have been replaced by braces, and braced strings will have become quoted strings.

The LITERAL token type is used for arbitrary text that bibclean does not examine further, such as the contents of a @Preamble{...} or a @Comment{...}.

The UNKNOWN token type should never appear in the output stream. It is used internally to initialize token type variables.


bibclean's support for the Scribe bibliography format is based on the syntax description in the Scribe Introductory User's Manual, 3rd Edition, May 1980. Scribe was originally developed by Brian Reid at Carnegie-Mellon University, and is now marketed by Unilogic, Ltd.

The BibTeX bibliography format was strongly influenced by Scribe, and indeed, with care, it is possible to share bibliography files between the two systems. Nevertheless, there are some differences, so here is a summary of features of the Scribe bibliography file format:

Letter case is not significant in field names and entry names, but case is preserved in value strings.
In field/value pairs, the field and value may be separated by one of three characters: =, /, or space. Space may optionally surround these separators.
Value delimiters are any of these seven pairs: { } [ ] ( ) < > ' ' " " ` `
Value delimiters may not be nested, even though with the first four delimiter pairs, nested balanced delimiters would be unambiguous.
Delimiters can be omitted around values that contain only letters, digits, sharp (#), ampersand (&), period (.), and percent (%).
Outside of delimited values, a literal at-sign (@) is represented by doubled at-signs (@@).
Bibliography entries begin with @name, as for BibTeX, but any of the seven Scribe value delimiter pairs may be used to surround the values in field/value pairs. As in (4), nested delimiters are forbidden.
Arbitrary space may separate entry names from the following delimiters.
@Comment is a special command whose delimited value is discarded. As in (4), nested delimiters are forbidden.
The special form


permits encapsulating arbitrary text containing any characters or delimiters, other than ``@End{comment}''. Any of the seven delimiter pairs may be used around the word ``comment'' following the ``@Begin'' or ``@End''; the delimiters in the two cases need not be the same, and consequently, ``@Begin{comment}''/``@End{comment}'' pairs may not be nested.

The key field is required in each bibliography entry.
A backslashed quote in a string will be assumed to be a TeX accent, and braced appropriately. While such accents do not conform to Scribe syntax, Scribe-format bibliographies have been found that appear to be intended for TeX processing.

Because of this loose syntax, bibclean's normal error detection heuristics are less effective, and consequently, Scribe mode input is not the default; it must be explicitly requested.


File extension of bibliography-specific initialization files. Default: .ini.
Name of bibclean initialization files. Default: .bibcleanrc (UNIX), bibclean.ini (non-UNIX).
Search path for bibclean and BibTeX input files. On UNIX, this is a colon-separated list of directories that are searched in order from first to last. It is not an error for a specified directory to not exist.

On other operating systems, the directory names should be separated by whatever character is used in system search path specifications, such as a semicolon on IBM PC DOS.

On Atari TOS, IBM PC DOS, IBM PC OS/2, Microsoft NT, and UNIX, search path for system executable files. The system-wide bibclean initialization file is searched for in this path.
On VAX VMS, search path for system executable files and the system-wide bibclean initialization file.


BibTeX and Scribe bibliography data base files.
File-specific initialization files.
UNIX system-wide and user-specific initialization files.
Non-UNIX system-wide and user-specific initialization files.


bibdup(1), bibextract(1), bibindex(1), biblex(1), biblook(1), bibparse(1), bibsort(1), bibtex(1), bibunlex(1), citefind(1), citetags(1), latex(1), scribe(1), tex(1).


Nelson H. F. Beebe
Center for Scientific Computing
Department of Mathematics
University of Utah
Salt Lake City, UT 84112
Tel: +1 801 581 5254
FAX: +1 801 581 4148
Email: <>