1,ed23,jon,doe,director,usa
2,ed23,jon,doe,director,usa
3,er67,jake,Kogan,director,usa
4,er67,jake,Kogan,director,usa
5,dc10,Charls,Morg,manager,usa
6,kc56,patel,Kumar,associate,india

2,ed23,jon,doe,director,usa
4,er67,jake,Kogan,director,usa
5,dc10,Charls,Morg,manager,usa
6,kc56,patel,Kumar,associate,india

$ cat input.txt
ID, uid  ,firstname ,lastname,   grade    , country n28
1 , ed23 , jon     ,   doe   ,  director  ,  usa
2 , ed23 ,  jon     ,  doe   ,  director     , usa
3 , er67 ,  jake     , Kogan ,  director     , usa
4 , er67 ,  jake     , Kogan ,  director     , usa
5 , dc10 ,  Charls     ,Morg ,  manager      , usa
6 , kc56 ,  patel     ,Kumar ,  associate    , india

$ awk -F' *, *' -v OFS=,
    'NR==1 {$1=$1;$0=$0; print; next};
     {id=$1; $1=""; $0=$0; if (!seen[$0]++) {print id $0}}' input.txt
ID,uid,firstname,lastname,grade,country n28
1,ed23,jon,doe,director,usa
3,er67,jake,Kogan,director,usa
5,dc10,Charls,Morg,manager,usa
6,kc56,patel,Kumar,associate,india

$ awk -F' *, *' -v OFS=,
   'NR==1 {$1=$1;$0=$0",count";print;next};
   {id=$1; $1=""; $0=$0; seen[$0]++; ids[$0]=id};
   END { for (id in ids) {print ids[id] id, seen[id]} }' input.txt  |
 sort -n
ID,uid,firstname,lastname,grade,country n28,count
2,ed23,jon,doe,director,usa,2
4,er67,jake,Kogan,director,usa,2
5,dc10,Charls,Morg,manager,usa,1
6,kc56,patel,Kumar,associate,india,1

awk -F, '{X=""; for (i=2;i<29;i++) X=X " " $i;}
     seen[X]!=1 {print;}
     {seen[X]=1;}' < input

$ tac file | awk -F , '{ key = $0; sub("[^,]*,", "", key) } !seen[key]++' | tac
2,ed23,jon,doe,director,usa
4,er67,jake,Kogan,director,usa
5,dc10,Charls,Morg,manager,usa
6,kc56,patel,Kumar,associate,india

$ tac file | awk -F , '{ key = $0; sub("[^,]*,", "", key) } key != prev; { prev = key }' | tac
2,ed23,jon,doe,director,usa
4,er67,jake,Kogan,director,usa
5,dc10,Charls,Morg,manager,usa
6,kc56,patel,Kumar,associate,india

$ tr ',' 't' < temp/testfile | uniq -f 1 | tr 't' ','
1,ed23,jon,doe,director,usa
3,er67,jake,Kogan,director,usa
5,dc10,Charls,Morg,manager,usa
6,kc56,patel,Kumar,associate,india

$ tac temp/testfile|tr ',' 't' | uniq -f 1 | tr 't' ','|tac
2,ed23,jon,doe,director,usa
4,er67,jake,Kogan,director,usa
5,dc10,Charls,Morg,manager,usa
6,kc56,patel,Kumar,associate,india