Following Chapter 6 of The TeXbook, I analyze the errors in the story.tex
file containing \errorcontextlines=0
in the beginning, and an erroneous control sequence: \centerline{\bf A SHORT \ERROR STORY}
. As expected, on running tex story.tex
, I get the following error:
! Undefined control sequence.
<argument> \bf A SHORT \ERROR
STORY
...
l.4 \centerline{\bf A SHORT \ERROR STORY}
But then, similar to what is suggested in the ending double-dangerous section, I type the following after the ?
prompt:
? I\errorcontextlines=100 \oops
(with space, as actually suggested in the book)
This gives the expected follow-up prompt:! Undefined control sequence. <insert> \errorcontextlines=10 \oops <argument> \bf A SHORT \ERROR STORY \centerline #1->\line {\hss #1 \hss } l.4 \centerline{\bf A SHORT \ERROR STORY}
? I\errorcontextlines=100\oops
(without space)
This gives unexpected prompt:! Undefined control sequence. <insert> \errorcontextlines=10\oops ... l.4 \centerline{\bf A SHORT \ERROR STORY}
(\oops
is an undefined control sequence.)
Question: This seems to suggest that TeX cares about the space in the above, but this seems wrong! What is going on here?