$ awk 'BEGIN{FS=OFS=","}{printf $1; for(i=0; i<$2; i++)printf("%sc%d",OFS, i ); print ""}' file
Joe,c0,c1,c2,c3
Tony,c0,c1
Peter,c0,c1,c2,c3,c4
Пояснение
awk 'BEGIN{
FS=OFS="," # set i/p and o/p field separator
}
{
printf $1; # print first field
for(i=0; i<$2; i++) # loop from 0 to value in second field
printf("%sc%d",OFS, i ); # printf format string
print "" # finally print newline char
}
' file