Shell Programming and Scripting

> cat file1
A B C
> cat file1 | tr " " "\n" >file1a
> cat file2 
B C A
> cat file2 | tr " " "\n" >file2a
> cat file3
A D C
> cat file3 | tr " " "\n" >file3a

> cat file1a | egrep -f file2a
A
B
C

> cat file1a | egrep -f file3a
A
C

awk 'BEGIN {
  n = split("A B C", t)
  for (i=1; i<=n; i++) _[t[i]]
  }
{
  for (i=1; i<=NF; i++)
    if (!($i in _)) {
      print "bad"
      next
    } 
  print "ok"
}'

zsh-4.3.9% awk 'BEGIN {
  n = split("A B C", t)
  for (i=1; i<=n; i++) _[t[i]]
  }
{
  for (i=1; i<=NF; i++)
    if (!($i in _)) {
      print "bad"
      next
    }
  print "ok"
}'
B C A
ok
A D C
bad