How to use sed to this substitution?

[phn737]

I have the following line in a file:
word1 -a<follow by some number here> word2
(eg: word1 -a23 word3)

I need to change &quot;-a23&quot; to &quot;-B aa=23&quot;. I am having a hard time trying to get this done in sed. Could someone please help.

Due to other substitution in my script done by sed, I like to have the substitution above done by sed if possible.

Thank you.

 

[jamisar]

on your exemple, in sed:
Q is a space!!
s/^\(.*\)Q-\([a-z]*[a-z]\)\([0-9]*[0-9]\)Q\(.*\)/\1 -B \2\2=\3 \4/ -----------
Ohne Intelligenz bist Du ein Fiasko,
ohne Technik ein Amateur und
ohne Herz eine Maschine.

[ Wladimir Horowitz ]

 

[phn737]

Thank you, jamisar, for replying to my post.

In the solution you provided, the substitution would appears to work (I have not actually try it yet) because the number, &quot;23&quot;, is known; but what if I do not know the number following the -a<###> ahead of time, how would I approach that case?

 

[phn737]

I tried the solution that jamisar provided, and getting this error:
sed: invalid option --B
...

There seem to be some syntax error in the solution.

 

[phn737]

By using the example below, this seem to be working fine for me and does what I wanted:

sed '/-a[0-9]*/s/-a/-B aa=/g'

Thank you, jamisar, for your assistance and effort.
We can end this post for now I will re-post if this give me any problem.