Shell Programming and Scripting

dog
cow
fox
cat
fish
duck
crow

cow cat fox dog
cow fox dog
fish crow fox dog cat 
cat dog duck
cow

awk     'NR==FNR        {T[$1]; next}
                        {for (i in T)
                                {if (T[i]!="Int")
                                   {if ($1==i || $NF==i) T[i]="Ext"
                                    for (j=2; j<NF; j++) if ($j==i) T[i]="Int"
                                   }
                                }
                        }
         END            {for (i in T) print i > T[i]}  
        ' file1 file2
  Int :
dog
crow
cat
fox
  Ext :
fish
duck
cow

awk 'NR==FNR{ A[$0]++; next }
    { for (i=1;i<=NF;i++)
        {
            if ($i in A) if (i == 1 || i == NF) { E[$i]++ } else { I[$i]++ }
        }
}
END { for (e in E) print e; print "----------------"; for (i in I) print i }
' file1 file2

$ awk 'NR==FNR{ A[$0]++; next }
>     { for (i=1;i<=NF;i++)
>         {
>             if ($i in A) if (i == 1 || i == NF) { E[$i]++ } else { I[$i]++ }
>         }
> }
> END { for (e in E) print e; print "----------------"; for (i in I) print i }
> ' file1 file2
fish
dog
duck
cow
cat
----------------
dog
crow
cat
fox
$

#!/bin/bash

while read X
do
    outfil=external.txt
    while read line
    do
        set $line
        if [[ $line =~ $X && ! $X =~ $1 && ! $X =~ ${@: -1} ]]; then
            outfil=internal.txt
            break
        fi
    done  < anim2
# remove quotes to export to files
    echo "$X >> $outfil"
done < anim1

#eof

# --- output ---
# dog >> internal.txt
# cow >> external.txt
# fox >> internal.txt
# cat >> internal.txt
# fish >> external.txt
# duck >> external.txt
# crow >> internal.txt