Shell Programming and Scripting

$ cat joh.txt
john::208:johnson
john::208:mery
john::208:test
john::207:test7
john::207:my7
admin:*:1:johnson
admin:*:1:test

$ awk -F ":" '{Arr[$1":"$2":"$3]=sprintf("%s,%s",Arr[$1":"$2":"$3],$4)} END {for ( i in Arr) {printf("%s:%s\n",i,Arr[i])}}'  joh.txt | sed 's/:,/:/'
admin:*:1:johnson,test
john::207:test7,my7
john::208:johnson,mery,test

> cat file 
john::208:johnson
john::208:mery
john::208:test
admin:*:1:johnson
admin:*:1:test
juan:u:107:juan
juan:u:107:jose
kyle:l:209:kyle

>awk '
function p_f ()
{
printf("%s",pf)
for (j=0;j<=i;++j)
   printf("%s",FS""a[j])
printf("\n")
i=0
}
{
f=$1FS$2FS$3
if ( f != pf &&  NR )
   p_f()
i++
a[i]=$NF
pf=f
}
END{
p_f()}
' FS=':' file
john::208::johnson:mery:test
admin:*:1::johnson:test
juan:u:107::juan:jose
kyle:l:209::kyle

awk 'BEGIN{FS=":";SUBSEP="@"}
{
 a[$1SUBSEP$2SUBSEP$3] =a[$1SUBSEP$2SUBSEP$3]" "$NF
}
END{
 for(i in a) {
   n=split(a[i],j," ")
   printf "%s:" ,i
   for( k=1;k<=n;k++) printf "%s " ,j[k]
   print ""
 }
}' "file"

# ./test.sh
kyle@l@209:kyle
juan@u@107:juan jose
admin@*@1:johnson test
john@@208:johnson mery test

awk 'BEGIN {FS = OFS = ":"}
!arr[$1$3] {arr[$1$3] = $0; next}
{arr[$1$3] = arr[$1$3] "," $4}
END {for(i in arr) {print arr[i]}}
' file