Shell Programming and Scripting

Name,Group,Email
Max,Group1,max@.com
Dan,Group2,dan@.com
Max,Group3,max@.com
Max,Group4,max@.com
Dan,Group5,dan@.com
Jim,Group6,jim@.com

Name,Group,Email
Max,Group1|Group3|Group4,max@.com
Dan,Group2|Group5,dan@.com
Jim,Group6,jim@.com

awk -F',' '{if(a[$1])a[$1]=a[$1]"|"$2","$3; else a[$1]=$2$3;}END{for (i in a)print i "," a[i];}' OFS=, FileInput

awk -F',' 'NR==1{print;next} {a[$1] = a[$1]"|"$2; b[$1] = $3} END {for (x in a){print x,substr(a[x],2),b[x]}}' OFS=, FileInput

awk '
BEGIN { FS = OFS = "," }
NR == 1 {print
        next
}       
!(($1,$3) in n) {
        n[$1,$3] = $1
        g[$1,$3] = $2
        e[$1,$3] = $3 
        next
}
{       g[$1,$3] = g[$1,$3] "|" $2 }
END {   for(i in n)
                print n[i], g[i], e[i]
}' FileInput

$ awk -F, '{_[$3]=(!(_[$3]))? $1 FS $2: _[$3] OFS $2}END{for(i in _)print _[i] FS i}' OFS="|" file

$ awk -F, '{Arr[$3]=!Arr[$3]? $1 FS $2: Arr[$3] OFS $2}END{for(i in Arr)print Arr[i] FS i}' OFS="|" file

Name,Group,Email
Dan,Group2|Group5,dan@.com
Jim,Group6,jim@.com
Max,Group1|Group3|Group4,max@.com

awk -F, '{arr[$3]=arr[$3]?arr[$3] OFS $2:$1 FS $2} END {for(i in arr) print arr[i] FS i}' OFS=\| file