Hello hi 123
if a equals b
you
one abc two three four
dany uri four 123

if if a equals b
dany dany uri four 123

sed 's/(^([ ]*[^ ]+[ ]+)[^ ]+[ ]+[^ ]+[ ]+[^ ]+[ ]*$)/2&/' $1 >>tmp

sed: -e expression #1, char 62: invalid reference 2 on `s' command's RHS

$ sed -nr '/^(w+)s+1s+(w+s*){3}$/p' file
if if a equals b
dany dany uri four 123

sed 's/s+(w+(s)?.?)+//' file

AAIT
AAL
AAME
AAOI
AAON