UNIX for Dummies Questions & Answers

awk '
BEGIN
{
FS="|";
}
{
a[$3]++;
if(a[$3]==2)
(
print v[$3] ORS $0; # v[$3] --> how it is meaning previous line not current line when we are processing line by line record, ORS= new line is it $0 Currecnt line
)
if(a[$3]>2)
(
print;
)
v[$3]=$0; # is this is assigning current line to v[$3] after every time .
}' file

awk '
BEGIN
{
FS="|";
}
{
a[Jon]++;  - a[Jon]=1
if(a[Jon]==2) --False hence a[Jon] count is 1
(
print v[Jon] ORS $0;
)
if(a[Jon]>2)  - False hence a[Jon] count is 1
(
print;
)
v[Jon]=$0; 
}' file

awk '
BEGIN
{
FS="|";
}
{
a[Jon]++; - a[Jon]=2
if(a[Jon]==2) --True hence a[Jon] count is 2
(
print v[Jon] ORS $0; - Here we can get previous line hence we are not overwrite the array of index 'Jon' So far now.
)
if(a[Jon]>2) - False hence a[Jon] count is 2 but not greater than 2
(
print;
)
v[Jon]=$0;  - Overwriting the the array of index 'Jon' 
}' file

awk '
BEGIN
{
FS="|";
}
{
a[Kate]++; - a[Kate]=1  -- Here Index is differs.
if(a[Kate]==2) --False hence a[Kate] count is 1
(
print v[Kate] ORS $0; 
)
if(a[Kate]>2) - False hence a[Kate] count is 1
(
print;
)
v[Kate]=$0; - Store current line if the same line exist will print that line with this line(as previous line)
}' file