Eric Blake wrote:
> > > /^test-freadptr.c/d
> >
> > ok so far.
Actually, that was not ok: it should be
/^test-freadptr.c$/d
> > > /^/test-freadptr.c/d
> >
> > This should be /^\/test-freadptr.c/d
Actually this should be
/^\/test-freadptr.c$/d
> > For me, with bash and sed-4.1.5, the result of both is
> > /^\/test-freadseek.sh$/d
> >
> > And on your side?
>
> Using bash 3.2 and set 4.1.5, and both commands gave
>
> /^\/test-freadseek.sh$/d
Ah! The culprit is the --posix option that gnulib-tool adds:
$ doubly_escaped_anchor='\\/'
$ echo 'test-freadseek.sh' | \
sed -e 's,/,\\/,g' -e "s,^,/^${doubly_escaped_anchor}," -e 's,$,\$/d,'
/^\/test-freadseek.sh$/d
$ echo 'test-freadseek.sh' | \
sed --posix -e 's,/,\\/,g' -e "s,^,/^${doubly_escaped_anchor}," -e 's,$,\$/d,'
/^/test-freadseek.sh/d
It ate not only the backslash but also the dollar sign. In fact, it affects
all three substitutions:
1) $ echo a/b | sed -e 's,/,\\/,g'
a\/b
$ echo a/b | sed --posix -e 's,/,\\/,g'
a/b
$ echo a/b | sed --posix -e 's,/,\\\/,g'
ab
$ echo a/b | sed --posix -e 's,/,\\\\/,g'
a/b
$ echo a/b | sed --posix -e 's,/,\\\\\/,g'
ab
$ echo a/b | sed --posix -e 's,/,\\\\\\/,g'
a/b
This looks like a bug to me: \\ expands to nothing. No way to produce a
backslash in the replacement.
2) $ echo foo | sed -e 's,^,/^\\/,'
/^\/foo
$ echo foo | sed --posix -e 's,^,/^\\/,'
/^/foo
$ echo foo | sed --posix -e 's,^,/^\\\/,'
/^foo
$ echo foo | sed --posix -e 's,^,/^\\\\/,'
/^/foo
This looks like a bug as well.
3) $ echo foo | sed -e 's,$,\$/d,'
foo$/d
$ echo foo | sed --posix -e 's,$,\$/d,'
foo/d
$ echo foo | sed --posix -e 's,$,$/d,'
foo$/d
And this?
Can you confirm my interpretations?
> POSIX says that \/ is not portable when / is not the delimiter.
In addresses (selection of lines), certainly. But it the 's' command? I cannot
find
the wording that says so.
Bruno
