UNIX for Dummies Questions & Answers

$ cat infile
xyc 1
xyd 1
xye 1
xyf 1
xyf 1
xyf 1
xyf 2
xyg 1
xyh 1
leg 2
$ cat script.awk
## For every line...
{
        ## Concatenate each number in a hash. The key will
        ## be the first field.
        data[ $1 ] = data[ $1 ] $2
}

## After processing file...
END {
        ## Variable that indicates if the field has not both numbers.
        bad = 0

        ## Go throught the hash.
        for ( idx in data ) {

                ## Check if both numbers are found, when one of them fails, set
                ## 'bad' variable and break the loop.
                for ( i = 1; i <= 2; i++) {
                        if ( ! index( data[idx], i ) ) {
                                bad = 1
                                break
                        }
                }

                ## Check 'bad' variable. If unset, both numbers were found, so
                ## print the key of the hash and reset variable for next loop.
                if ( ! bad ) {
                        printf "%s\n", idx
                }
                bad = 0
        }
}
$ awk -f script.awk infile
xyf

perl -lane '
if (defined $x{$F[0]} && $x{$F[0]} == $F[1]) { # Check if the 1st field is already defined and is equal to 2nd field in associative array %x
    $y{$F[0]}++; # If so, increment the count of 1st field in another array %y
}
else {
    $x{$F[0]} = $F[1]; # If 1st field doesn't exist, then store it and 2nd field in array %x
    $y{$F[0]}++; # Increment count of 1st field in array %y
}
END {
    for (keys %y) { # Loop through the keys of %y
        ($y{$_} > 1) && print $_; # If count of 1st field is more than 1, then print the corresponding key
    }
}' myTextFile

n12:/home/vbe/wks/z $ if [ $(sort -k 2 infile|tail -1|read VALUE NUMVAL;grep $VALUE infile|uniq|wc -l) -gt 1 ];then echo VALUE=$VALUE;fi 
VALUE=xyf