Duplicate lines that included same strings after /film/

Question

Explaining is hard I want to start with example. Please see the Bold text.

I have very long list like the following list :

http://dl3/film/**Daylights.End**.3*******************
http://dl45/film/**The.Wild.Life**.720***************
http://dl45/film/**The.Wild.Life**.10***************
http://dl3.pw/film/T**he.Wild.Life**.2*******************
http://dl45/film/**Daylights.End**.2*******************

I want to find all Duplicate lines that included same strings after /film/, but I don’t want to search the line to the end, the search should look for duplicate strings just like 10 or 20 characters after /film/

• The strings after /film/ are different.
• The method should search a list with like 5 thousand line and find all duplicate line and maybe after founding delete, cut, copy or mark One or Two of them.

Thanks in advance

Answer 1

Try

sed -n 's/^/@/' > newfile

or

sed -ni 's/^/@/'

Both commands are inserting an @ at the beginning every libe of your last command.

Answer 2

nice, command output for

cat long-list |grep -Eo '/film/.{15}' |sort |uniq --repeated

is a list that contain all duplicate names. now how can i mark all duplicate line with something like a @ in start line?