Hi Ravinder,
Note that your code is adding a field separator when joining alphanumeric data lines. (I'm guessing this is because carlr didn't use CODE tags when presenting the sample input and output files and you copied the sample data before Scrutinizer edited that post to include the tags that made the <space> at the start of the line that needed to be joined visible.)

Hi Scrutinizer,
I like your suggested awk script and it works perfectly for the sample data given. Unfortunately, the sample data carlr provided doesn't agree with the description of the actions to be taken:
Note that the line shown in red does not meet the requirement shown in red. The line to be combined starts with a <space>; not an uppercase alphabetic character. Your code compensated for that inconsistency by looking for a non-digit instead of looking for an uppercase alpha.

I'm guessing that what carlr really wants to do is join any lines that contain anything other than digits and a possible decimal point. This would allow input like:

Code:

862.8
MULTIPLE AND UNSPECIFIED INTRATHORACIC ORGANS WITHOUT MENTION OF
 OPEN WOUND INTO CAVITY
862.9
2 OR MORE AND UNSPECIFIED INTRATHORACIC ORGANS WITHOUT MENTION O
F OPEN WOUND INTO CAVITY
863
INJURY TO GASTROINTESTINAL TRACT

to be turned into:

Code:

862.8
MULTIPLE AND UNSPECIFIED INTRATHORACIC ORGANS WITHOUT MENTION OF OPEN WOUND INTO CAVITY
862.9
2 OR MORE AND UNSPECIFIED INTRATHORACIC ORGANS WITHOUT MENTION OF OPEN WOUND INTO CAVITY
863
INJURY TO GASTROINTESTINAL TRACT

instead of the output your script produces:

Code:

862.8
MULTIPLE AND UNSPECIFIED INTRATHORACIC ORGANS WITHOUT MENTION OF OPEN WOUND INTO CAVITY
862.9

2 OR MORE AND UNSPECIFIED INTRATHORACIC ORGANS WITHOUT MENTION O
F OPEN WOUND INTO CAVITY
863
INJURY TO GASTROINTESTINAL TRACT

If input like this is a concern to the submitter, something like this (that I had created before I saw Scrutinizer's suggestion):

Code:

awk '
{	d2 = ($0 ~ /[^0-9.]/) ? "" : ORS
	d1 = (d2 && NR > 1) ? d2 : ""
	printf("%s%s%s", d1, $0, d2)
}
END {	if(!d2)	print ""
}' file

or (using Scrutinzer's code as a base):

Code:

awk 'END{if(ORS==x)printf RS} {ORS=x} !/[^0-9.]/{if(NR>1)printf RS; ORS=RS}1' file

might work better.