awk 'NR>1{ ###checking here if line number is greater than 1 here, if yes then perform following steps.
                if($4 !~ /del/ && $4 !~ /ins/){ ###Checking here if 4th field is NOT having del and ins strings in them.
                                                REF=substr($4,index($4,">")-1,1); ###creating variable REF which is a substring starting from index of char > -1 to 1 character.
                                                OBS=substr($4,index($4,">")+1,1) ###creating variable OBS which is having substring of 4th field whose starting index is the index number of > +1 to till 1 character.
                                              }
                else                          { ###If a line does not have ins and del strings within them then perform following actions.
                                                e=$4; ###creating a variable named e whose value is 4th field.
                                                if($4 ~ /ins/){ ###checking if 4th field has ins string in it.
                                                                sub(/.*ins/,"",e); ###substituting all characters from starting to till ins string with NULL in e variable.
                                                                REF=""; ###Making variable REF to NULL.
                                                                OBS=e ###Making variable named OBS to new value of variable e now.
                                                              };
                                                if($4 ~ /del/){ ###Checking here if any 4th field has string del in it.
                                                                sub(/.*del/,"",e); ###substituting all characters from starting to till string del with NULL in variable named e.
                                                                REF=e; ###creating variable REF to new value of variable e here.
                                                                OBS="" ###creating OBS variable with NULL value.
                                                              }
                                              };
                CHR=substr($7,1,index($7,":")-1); ###creating variable CHR with substring whose starting point is 1st position to till index of colons index -1.
                CHR_1=substr($7,index($7,":")+1,index($7,"-")-4);### creating variable named CHR_1 with a substring whose starting point is index of colon +1 till index of dash -4 value in 7th field.
                CHR_2=substr($7,index($7,"-")+1);### creating a variable named CHR_2 here whose value is substring whose starting point is index of dash value +1 till the end of 7th field value.
                if($4 !~ /ins/)               { ###Checking if 4th field does not have ins string in it, if yes then perform following.
                                                print "chr"CHR,CHR_1 CHR_2$4,"REF="REF,"OBS="OBS,$1  ###printing values of variables CHR,CHR_1,CHR_2 etc.
                                              }
                else                          { ###Checking if 4th field does not have ins value in it, then perform following.
                                                print "chr"CHR,CHR_1,CHR_2,$4,"REF="REF,"OBS="OBS,$1 ###print the value of variables CHR,CHR_1,CHR_2 etc.
                                              }
         }
    ' Input_file                                ###Mentioning the Input_file name here.