1 awk ' # num.collapse
2 #   Input:  lines of form: string (tab) num1 [(space) num2]
3 #   Output: lines of form: string (tab) fancy.num.list
4 #
5 #   fancy.num.list contains items, separated by ", ", of form: num or num-num
6 #	Sequence of input lines with same value of string is combined
7 #	into a single output line.  Each input line contributes either
8 #	num or num-num to output line.
9 
10 BEGIN	{ FS = OFS = "\t" }
11 
12 	{ sub(/ /, "\\(en", $2) }  # use - if there is no en dash
13 
14 $1 != p	{ p = $1
15 	  if (NR > 1) printf "\n"
16 	  printf "%s\t%s", $1, $2
17 	  next
18 	}
19 	{ printf ", %s", $2 }
20 END	{ if (NR > 0) printf "\n" }
21 ' $*