[BusyBox] More wandering through busybox sed source...

[Rob Landley]

On Saturday 13 September 2003 21:54, Glenn McGrath wrote:

> I think acording to posix 's/a/b/;s/b/c/' and 's/a/b/ s/b/c/' are
> supposed to be the same
>
> But now im confused acording to posix is 's/a/b/ g' one command or two ?
>
>
> Posix says
>
> The script shall consist of editing commands of the following form:
>
> [address[,address]]function
>
> The command can be preceded by <blank>s and/or semicolons. The function
> can be preceded by <blank>s. These optional characters shall have no
> effect.

In this case, the g is an option to the s command, not the start of a new 
command.  gnu sed is parsing it as such, and complaining that it doesn't know 
what a space means as an option to the s command.  It's not clear where the 
previous command terminated (unless you're allowed to just terminate it with 
the first thing you don't recognize).  I thought that was what the semicolons 
were for.

Can you just run together commands otherwise?  (Who wrote this spec?)

> Command verbs other than {, a, b, c, i, r, t, w, :, and # can be followed by
> a semicolon, optional <blank>s, and another command verb. However, when the
> s command verb is used with the w flag, following it with another command in
> this manner produces undefined results.

Okay, so when you do NOT use the w flag, then a space (or basically anything 
else you don't recognize) should mark the start of a new command.  That 
positively sucks, and gnu gets it wrong.  It means that adding flags in 
future could break existing scripts, although I guess that's what the 
semicolon is for...

On a side note, I notice that numeric and w flags to the s command aren't 
implemented yet.  Would it help if I compiled a list of stuff like this, or 
do you have one?

> Glenn

Rob