[NTG-pdftex] pdfinitex != pdftex --ini?

What is the difference between pdfinitex and pdftex --ini? hahe@hahepc1:~$ pdfinitex y This is pdfeTeXk, Version 3.141592-1.20a-rc1-2.1 (Web2C 7.5.2) %&-line parsing enabled. kpathsea: Running mktexfmt pdfinitex.efmt fmtutil: no info for format `pdfinitex'. I can't find the format file `pdfinitex.efmt'! hahe@hahepc1:~$ pdftex --ini y This is pdfeTeXk, Version 3.141592-1.20a-rc1-2.1 (Web2C 7.5.2) (INITEX) %&-line parsing enabled. output format initialized to DVI (./y.tex ! Missing { inserted. <to be read again> { l.1 \hbox{ abc} ? Shouldn't the first behave as the second? Man page says --ini: Be pdfinitex... Regards, Hartmut