bash conditionnal getline with awk/tr/sed?

Question

I'm struggling with this, i want to concatenate a group of lines into a single one line/row. Each line (titi/toto/tata) of my file has 2 or 3 fields separated by a ";" So my input is like this:

titi1
titi2 
titi3
43;75;97
1;2;87
toto1
toto2
toto3
40;50;60
tata1
tata2
tata3
4;5;2
5;3;7
2;5;9

I need this output :

titi1;titi2;titi3;43;75;97
titi1;titi2;titi3;1;2;87
toto1;toto2;toto3;40;50;60
tata1;tata2;tata3;4;5;2
tata1;tata2;tata3;5;3;7
tata1;tata2;tata3;2;5;9

So has you can see the first 3 lines are informations (toto/tata etc...) that should be repeated for each line after that start with a number.

First my input had only one line with number so it was a grouping 4 by 4. so i searched in the forum had i found an example and did this with a getline like this :

awk '{getline b; getline c; getline d;printf("%s %s %s %s\n",$0,b,c,d)}'

But then i started to have 2 or even 3 lign with numbers... So i'm struggling doing a 'conditionnal' that understand that it should repeat the first 3 lign everytime it sees a lign starting with a numbers.

Answer 1

Could you please try following.

awk '
{
  sub(/ +$/,"")
}
/^[a-zA-Z]+/{
  if(val && flag){
    val=""
  }
  val=val?val ";" $0:$0
  flag=""
  next
}
{
  flag=1
  print val ";" $0
}'  Input_file

Solution 2nd: In case your Input_file could have last line as tot etc and you want to print it too then use following.

awk '
{
  sub(/ +$/,"")
}
/^[a-zA-Z]+/{
  if(val && flag){
     val=""
  }
  val=val?val ";" $0:$0
  flag=""
  next
}
{
  flag=1
  print val ";" $0
}
END{
  if(val && !flag){
     print val
  }
}'  Input_file

Answer 2

$ awk -F';' 'NF>1{print s $0; p=1; next} p{s=p=""} {s=s $0 FS}' file
titi1;titi2;titi3;43;75;97
titi1;titi2;titi3;1;2;87
toto1;toto2;toto3;40;50;60
tata1;tata2;tata3;4;5;2
tata1;tata2;tata3;5;3;7
tata1;tata2;tata3;2;5;9

wrt your original script - see http://awk.freeshell.org/AllAboutGetline for why not to use getline for this (or most other situations) and how to call getline correctly on those rare occasions when it is appropriate to do so.