I have teh follwing details in a file:

SmithA..... ,,400
JonesA..... ,,300
JamesA..... ,,600
BakerA ,,800
ChrisA ,,1200


the first field name is 6 characters in length always and alays ends with an 'A'.
The periods denote white space (space caharacters), as you can see on certain occurences ther are many 'spaces' and in other instances no 'spaces'.

I want to be able to make the above file as below:

SmithA. ,,400
JonesA. ,,300
JamesA. ,,600
BakerA. ,,800
ChrisA. ,,1200

So anly one single whitespace is present after the las 'A' character.
I have treied the following,

sed 's/ *//g' fileA > fileB
which gives me:

SmithA ,,400
JonesA ,,300
JamesA ,,600
BakerA ,,800
ChrisA ,,1200

however i am now not so sure how to put a whitecase character back in after the A to get the format as required above.
Could anyone assist, also would perferably be ideal if i could have the whole thing processed in one single sed command.

Try this:

Regards