Além de haver poucas ferramentas especiais para trabalhar com csv (por exemplo, csvtool )
awk -F"|" '
{
r = $w SUBSEP $x SUBSEP $y SUBSEP $z #prepare index from 4 fields data
}
R[r]{ #if index present in array already
if ( R[r] != 1){ #if it is a first repetition
print R[r] #print line stored in array
R[r] = 1 #mark element «not a first time»
}
print #print present line
next #pass rest of code(goto next line)
}
{
R[r] = $0 #store line in array (first time only)
}
' w=$ColumnNo1 x=$ColumnNo2 y=$ColumnNo3 z=$ColumnNo4 file.csv