Eric Blake <ebb9 <at> byu.net> writes:
> cat <<EOF
> -3. $LINENO
> -4. $LINENO
> +5. $LINENO
> +6. $LINENO
> +7. \$LINENO
> EOF
> $ @kbd{sed '=' <lineno |}
> @@ -14493,16 +14534,28 @@ Special Shell Variables
> > @kbd{ ' |}
> > @kbd{ sh}
...
> +7. \7
Ouch. Our sed preprocess has the possibility of generating non-portable child
scripts. Anywhere where the parent script uses:
cat >>child <<EOF
AS_ESCAPE([text], [$`])
EOF
then any instances of $LINENO in text will be turned into \$LINENO. But since
the sed preprocess currently munges that instance, the \ is no longer quoting a
special character, so we have inserted a raw \ into the child script. In turn,
as demonstrated by the above simple example, we could be causing other
portability nightmares such as calling the non-portable 'echo "\7"' instead of
the intended 'echo "$LINENO"' in a shell with LINENO support.
But is it even possible to write the sed script more robustly, as we really
don't know the difference between here-doc contents and other instances of
\$LINENO?
--
Eric Blake
