insert one file into middle of another file

Shell Programming and Scripting
1

how to insert one file into another file not by concatenating as usual done.
file1
A B
C D
E F
G H
I J
K L

file2
23455
33444
33334
33345

Output shud be
23455
A B
C D
33444
E F
G H
33345
I J
K L

2

probably an easier way than this, but it does work :

#  paste -s -d "\t\n" file1 | paste file2 - | tr "\t" "\n"
23455
A B
C D
33444
E F
G H
33334
I J
K L
33345
3

also - can use cat for legibility:

#  cat file1 | paste - - | paste file2 - | tr "\t" "\n"

does same as 1st ans..

4

33334
I J
K L
33345

[/CODE]
[/quote]

Thanks.....

5 
awk 'FNR==NR{ a[FNR]=$0;next }
{ 
  print $0
  print a[FNR+l]
  l++
  print a[FNR+l]
}
' file file1

output

# ./test.sh
23455
A B
C D
33444
E F
G H
33334
I J
K L
33345