Shell Programming and Scripting

1 aa rep
1 dd rep
1 kk rep
2 bb sad
2 ss sad
3 ee dam

1 apple  fruit
2 mango tree
3 lilly flower

1 aaple fruit aa,dd,kk rep
2 mango tree bb,ss sad
3 lilly flower ee dam

awk 'NR == FNR {
  k[$1] = k[$1] ? k[$1] "," $2 : $2
  l[$1] = $3; next
  }
{
  print $0, k[$1], l[$1]
  }' file1 file2

zsh-4.3.11[t]% head file[12]
==> file1 <==
1 aa rep
1 dd rep
1 kk rep
2 bb sad
2 ss sad
3 ee dam

==> file2 <==
1 apple  fruit
2 mango tree
3 lilly flower
zsh-4.3.11[t]% awk 'NR == FNR {
  k[$1] = k[$1] ? k[$1] "," $2 : $2
  l[$1] = $3; next
  }
{
  print $0, k[$1], l[$1]
  }' file1 file2
1 apple  fruit aa,dd,kk rep
2 mango tree bb,ss sad
3 lilly flower ee dam

1 apple  fruit 
aa,dd,kk rep
2 mango 
tree bb,ss sad
3 lilly 
flower ee dam

awk 'NR==FNR{a[$1]=a[$1]","$2;b[$1]=$3;next} b[$1] {print $0,a[$1],b[$1]}' file1 file2

od -bc file2 | head