Shell Programming and Scripting

COL1 COL2
ABC    111asdf
ABC    222dfgh
ABC    333fghy
ABC    4rtyu
XYZ    1yuio
XYZ    2ytre

COL1     COL2
ABC    '111asdf','222dfgh','333fghy','4rtyu'
XYZ     '1yuio','2ytre'

awk 'NR==1 { print ; next }
{ A[$1]=A[$1]","$2 }
END { for(X in A) print X,substr(A[X],2) }' inputfile

awk '
        NR == 1 {
                print $1 "\t" $2
        }
        NR > 1 {
                A[$1] = A[$1] ? A[$1] OFS "\x27" $2 "\x27" : "\x27" $2 "\x27"
        }
        END {
                for ( k in A )
                        print k "\t" A[k]
        }
' OFS=, file

COL1    COL2
ABC     '111asdf','222dfgh','333fghy','4rtyu'
XYZ     '1yuio','2ytre'

awk '
  NR>1 {
    $2=q $2 q
  }
  $1!=p {
    if(NR>1) print s
    s=$1 "\t" $2
    p=$1
    next
  }
  {
    s=s "," $2
  }
  END{
    print s
  }
' q=\' file

awk '
NR==1 { printf("%s\t%s", $1, $2) ; next }
{ff=""; of=",%s"; if (!a[$1]++) { ff=$1; of="\n%s\t"; } printf ( of "\x27%s\x27", ff, $2); }
END {print ""}' infile