How to abbreviate author's firstname in bibliography

Assuming that you're otherwise satisfied with the formatted output produced by the bibliography style unsrtdin -- i.e., if the only thing you want to change in the style file is to force BibTeX to always abbreviate first names down to their initials -- you could proceed as follows:

• Make a copy of the file unsrtdin.bst and call it, say, myunsrtdin.bst. (Never edit the original style file directly.)

• Open the file myunsrtdin.bst in your favorite text editor.

• Search for the following line (in the function format.names):

  { s nameptr "{ff~}{vv~}{ll}{, jj}" format.name$ 't :=
  

  and change it to

  { s nameptr "{f.~}{vv~}{ll}{, jj}" format.name$ 't :=
  

• Next, in the function format.crossref.editor, search for the line

      { editor #2 "{ff }{vv }{ll}{ jj}" format.name$ "others" =
  

  and change it to

      { editor #2 "{f. }{vv }{ll}{ jj}" format.name$ "others" =
  

• Save the file and start using it by issuing the instruction bibliographystyle{unsrtdin}.

---

I can't help but make a few remarks about the use of Zotero. You've already discovered one inconsistency: Sometimes the tool provides full first names of authors and editors, at other times it provides only abbreviated first names. Sadly, this is likely going to be the least of your worries with Zotero's output. Be sure to always check the .bib file (or files) generated by this tool for correctness of all input fields. In my own experience with Zotero, its output can contain quite a few embarrassing typos and, much worse, outright errors, such as missing authors in a multi-author publication.

This piece of advice about double-checking the validity of the files generated by Zotero (or any other online tool like it!) is independent of whether you end up using unsrtdin/BibTeX or biblatex/biber: BibTeX and bibLaTeX can do nothing about errors contained in the inputs they operate on.

I tried to follow the description of Mico but needed some addaptions. This is the patch I applied to the current version of unsrtdin.bst (http://www.ctan.org/tex-archive/biblio/bibtex/contrib/german/din1505) to obtain abbreviated first names:

diff --git a/unsrtdin_mod.bst b/unsrtdin_mod.bst
index 5505961..5134bfb 100644
--- a/unsrtdin_mod.bst
+++ b/unsrtdin_mod.bst
@@ -448,7 +448,7 @@ FUNCTION {format.names}
        s nameptr "{ll}" format.name$ 't :=
        t capitalize 't :=
        s nameptr "{ jj}" format.name$ 'w :=
-       s nameptr "{, ff}{ vv}{ jj}" format.name$ 'u :=
+       s nameptr "{, f.}{ vv}{ jj}" format.name$ 'u :=
        u  text.length$  'lang :=
        #1 'zahl :=
        "" 'v :=
@@ -1192,7 +1192,7 @@ FUNCTION {format.crossref.editor}
     { pop$ ua.etal * }%% --->u. a.
     { #2 <
         'skip$
-        { editor #2 "{ff }{vv }{ll}{ jj}" format.name$ "others" =
+        { editor #2 "{f. }{vv }{ll}{ jj}" format.name$ "others" =
             { ua.etal }

             { " ; " * editor #2 "{vv~}{ll}" format.name$ * " (Hrsg.)" * }

Edit : For the current version (3.12) of biblatex, firstinits argument is depreciated. Use giveninits instead (cf. this question).

---

When using biblatex, just state this in your preamble:

usepackage[backend=bibtex,firstinits=true]{biblatex}

If you want to add an unsorted style use this:

  usepackage[backend=bibtex,style=numeric-comp,sorting=none,firstinits=true]{biblatex}

I currently use this line:

 usepackage[backend=bibtex,citestyle=numeric-comp,bibstyle=ieee,sorting=none,minbibnames=5,maxbibnames=5,defernumbers=true,firstinits=true]{biblatex}

This allows for multiple bibliographies, limits the amount of reference names to 5, and uses a different citing and bibliography style.

# FILENAME: abbrv_bib.py

#!/usr/bin/env python3
from bibtexparser.bwriter import BibTexWriter
import bibtexparser
from pybtex.database import parse_file
import argparse
parser = argparse.ArgumentParser()
parser.add_argument('input', help='input file name')
parser.add_argument('output', help='output file name')
parser.add_argument('--no-middle', action='store_true',
                    help='do not abbreviate middle name')
args = parser.parse_args()

# %%
# Parse the original bib file with pybtex
# pybtex can distinguish first/middle/last names
bib_database = parse_file(args.input)
for k in bib_database.entries.keys():
    item = bib_database.entries[k]
    persons = item.persons
    print(k)
    for i in range(len(persons['author'])):
        oldFirstNames = persons['author'][i].first_names
        newFirstNames = []
        for j in oldFirstNames:
            if j[-1] == '.':
                newFirstNames.append(j)
            else:
                newFirstNames.append(j[0].upper() + '.')

        oldMiddleNames = persons['author'][i].middle_names
        if args.no_middle:
            newMiddleNames = oldMiddleNames[:]
        else:
            newMiddleNames = []
            for j in oldMiddleNames:
                if j[-1] == '.':
                    newMiddleNames.append(j)
                else:
                    newMiddleNames.append(j[0].upper() + '.')

        oldName = ' '.join(
            [' '.join(persons['author'][i].last_names) + ','] + oldFirstNames + oldMiddleNames)
        newName = ' '.join(
            [' '.join(persons['author'][i].last_names) + ','] + newFirstNames + newMiddleNames)
        if (oldName != newName):
            print('  - {:s} => {:s}'.format(oldName, newName))
            persons['author'][i].first_names = newFirstNames
            persons['author'][i].middle_names = newMiddleNames


# %%
# Write the new bib file with bibtexparser
# I use bibtexparser here because pybtex prefers quote instead of curly bracket
# e.g.  pybtex:  title = "This is a paper"
#       bibtexparser: title = {This is a paper}
# This makes it escape some underscores incorrectly
with open(args.input, 'r', encoding='utf-8') as bibtex_file:
    bibtex_str = bibtex_file.read()
bib = bibtexparser.loads(bibtex_str)
for k in bib.entries_dict:
    bib.entries_dict[k]['author'] = ' and '.join(['{:s}, {:s} {:s}'.format(' '.join(p.last_names), ' '.join(p.first_names), ' '.join(p.middle_names))
                                                  for p in bib_database.entries[k].persons['author']])
writer = BibTexWriter()
with open(args.output, 'w', encoding='utf-8') as bibfile:
    bibfile.write(writer.write(bib))

I wrote a python script to do it manually. This avoids incompatibility of biblatex to other package. You can use it as

python3 abbrv_bib.py input.bib output.bib

If you don't want to abbreviate middle name, just add the argument --no-middle The script can abbreviate the following types of name:

Cruden, Brett A. => Cruden, B. A.
Johann Sebastian Bach => Bach, J. S.
Surname, Given Name III. => Surname, G. N. III.
Johann Sebastian Jr. Bach => Bach, J. S. Jr.

It also rearrange the name to Last name, First name Middle name