On Wed, Jun 06, 2012 at 02:06:19PM +0300, Borislav Borisov wrote:
> > Ok. So we forgot about exportfs "*:/path",
> > which is shown as /path <world>.
> >
> > I'd like to have it anchored.
> > oes this still work for you?
> >
> > + sed -e '$! N; s/\n[[:space:]]\+/ /; t;
> > s/[[:space:]]\+\([^[:space:]]\+\)\(\n\|$\)/ \1\2/g; s/ <world>$/ */g; P;D;'
>
>
> To some extent it does... it will catch the ones that end with <world>, but
> the problem is the search and replaces used are appending a newline. Also,
> I initially missed a replace after the first search and replace. Eventually
> I ended up with something close to what you want:
> sed -e '$! N; s/\n[[:space:]]\+/ /; s/ <world>$/ */g; t;
> s/[[:space:]]\+\([^[:space:]]\+\)\(\n\|$\)/ \1\2/g; s/ <world>\(\n\|$\)/
> *\1/g; P;D;'
>
> That one, however, is bugging me a lot.
It is not even strictly correct, I think.
You need to change the order of the first too substitutions for the "t;"
to be correct. See below.
> So I came up with another solution,
> which of course isn't anchored either, but is more readable:
> sed -n '1h; 1!H; ${g; s/[[:space:]]\+\([^[:space:]]\+\)\(\n\|$\)/ \1\2/g; s/
> <world>/ */g; p}'
I don't like that this is first reading all of it,
then do a replace over all of it.
It also breaks if you have white space in path names (which is probably
a very bad practise, in case it is even legal ;-)
> I do not consider myself a sed guru, maybe someone who is can figure a
> better approach.
I think this one is correct, please see if you can break it.
sed -e '$! N;s/\n[[:space:]]\+<world>/ */; s/\n[[:space:]]\+/ /; t;
s/[[:space:]]\+\([^[:space:]]\+\)\(\n\|$\)/ \1\2/; s/ <world>\(\n\|$\)/ *\1/;
P;D;'
Note that I dropped the /g from the latter substitutions.
FMTYEWTK:
$! N; # append next line, unless end of file
s/\n[[:space:]]\+<world>/ */;
# join continuation lines and replace <world>, if present.
s/\n[[:space:]]\+/ /;
# join continuation lines. can not succeed if previous line succeeded.
t; # if one of the previous two "join lines" succeeded,
# print and start new cycle.
# else:
# we have one single line record,
# and a potentially partial record as second line
s/[[:space:]]\+\([^[:space:]]\+\)\(\n\|$\)/ \1\2/;
# squeeze spaces between path and client spec
# If we put a /g on there, it may also squeeze spaces
# within the path spec of a trailing partial record.
# Which is why I left it off now.
# Not sure why I put it in there in the first place.
s/ <world>\(\n\|$\)/ *\1/;
# if the client spec is <world>, substitute by *
P; # print up to the first newline
D; # delete up to the first newline and start new cycle
If we can be sure that exportfs output will always be \n terminated,
we could leave off the \(\n\|$\) ... \... parts.
Would it be easier to the eye if we break it up into single statements?
sed -e '$! N;' \
-e 's/\n[[:space:]]\+<world>/ */;' \
-e 's/\n[[:space:]]\+/ /;' \
-e 't;' \
-e 's/[[:space:]]\+\([^[:space:]]\+\)\(\n\|$\)/ \1\2/;' \
-e 's/ <world>\(\n\|$\)/ *\1/;' \
-e 'P;D;'
Again, please, everybody:
try to break this with any output exportfs may produce.
If only ... I mean, well, it is 2012, right?
ah well, never mind :-/
--
: Lars Ellenberg
: LINBIT | Your Way to High Availability
: DRBD/HA support and consulting http://www.linbit.com
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