awk help

Shell Programming and Scripting
1

Dear Members,
I need a help about manupulating a text file; The contents are like;

MNTRANKPC087559 MNTRANKPC086921 MNTRANKPC109675 MNTRANKPC094376 :a1360
MNTBTRN00084114 MNTBTRN00123212 :a8483
MNTBTRN00056800 MNTRANKPC109765 MNTBTRN00056800 :a9089
MNTBTRN00011953 MNTBTRN00055437 :b2134
MNTBTRN00056618 MNTBTRN00056618 :b3591
MNTRANKPC114848 MNTRANKPC114848 :b3884
mntbtrn00146067 MNTBTRN00120769 :b3970
MNDEMUCTS2P187 MNDEMUCTS2P528 MNDEMUCTS2P128 MNDEMUCTS2P195 MNDEMUCTS2P040 MNDEMUCTS2P419 :b6052
MNTBTRN00055027 MNTRANKPC086922 :b6262
MNTRANKPC109690 MNTRANKPC109615 :c3788
MNTBTRN00045347 MNTBTRD00030373 :c6043
MNTBTRN00121867 MNTBTRN00023939 MNTBTRN00038590 :c6063
MNTBTRN00056712 MNTBTRN00056712 MNTBTRN00056712 :c6781
MNTBTRD00047186 :c9362
MNTBTRN00137582 MNTBTRN00111419 MNTBTRN00144817 :d0189
MNTBTRN00059593 MNTRANKPC113100 :d1756
MNTBTRN00021952 MNTBTRN00017771 MNTRANKPC114847 :d2289
MNTBTRD00031053 MNTBTRN00059593 MNTBTRD00139444 :e0653
MNTBTRN00000042 MNTBTRN00000042 MNTBTRN00059367 :e1243
MNTBTRD00139444 MNTBTRN00000052 MNTBTRD00139444 MNTRANKPC109675 :e3341
MNTBTRN00130620 MNTBTRN00130620 :e4534
MNTBTRD00030188 MNTRANKPC112829 :e6253
MNTBTRN00011956 MNTBTRN00011956 MNTBTRN00011956 MNTBTRN00011956 MNTBTRN00011956 MNTBTRN00011956 MNTBTRN00011956 MNTBTRN00011956 :e7233
MNTBTRN00011601 MNTBTRN00126655 :e9442
MNTBTRN00037633 MNTBTRN00146063 :f0226
MNTBTRD00143519 MNTRANKPC105541 :f5344
MNTBTRN00120764 MNDEMUCPC112129 :g8947
MNTBDED00040638 MNTBDED00040718 MNDEMUCPC115172 :g9531
MNTBTRN00021931 MNTBTRN00021931 :ut3ob
MNTBTRN00045345 MNTBTRN00120772 :ut4ta

What I want is ;

4:a1360
2:a8483

and goes to the end of each record.Explaination for first row of the text file is 4:a1360 Why?
because there are MNTRANKPC087559 MNTRANKPC086921 MNTRANKPC109675 MNTRANKPC094376 (total 4 columns) till :a1360
If I am talking for the second row 2:a8483 Because there are MNTBTRN00084114 MNTBTRN00123212 (total 2 columns) till to the :a8483

How Can I manipulate my text file?

Thank you very much for your concern

2

Any attempts / ideas / thoughts from your side?

Do you want those two lines only? Or an equivalent output for every single input line?

3 
awk '$0=(NF-1)$NF' input_file
4

Dear Moderator;
I want to get lines as my code explained then redirect results to a new file

5

The question was more if you made up your mind on how to tackle this problem; any preferred tools? Any algorithm? Any attempt, even if it failed?
And, there was a second question as well.

6

I want to thank to rdrtx1 beccause;

awk '$0=(NF-1)$NF' input_file

AND my output is;

4:a1360
2:a8483
3:a9089
2:b2134
2:b3591
2:b3884
2:b3970
6:b6052
2:b6262
2:c3788
2:c6043
3:c6063
3:c6781
1:c9362
3:d0189
2:d1756
3:d2289
3:e0653
3:e1243
4:e3341
2:e4534
2:e6253
8:e7233
2:e9442
2:f0226
2:f5344
2:g8947
3:g9531
2:ut3ob
2:ut4ta

That's what I want

------ Post updated at 04:35 PM ------

awk '$0=(NF-1)$NF' input_file

is my solution from rdrtx1