How to find the particular text stored in the file “data.txt” and it occurs only once

Question

The line I seek is stored in the file data.txt and is the only line of text that occurs only once.

How do I go about finding that particular line using linux?

Answer 1

Add more information to you post. How data.txt look like? Like this:

11111111
11111111
pass1111
11111111

Or like this

afawfdgd
password
somethin
gelse...

And, do you know the password is in file or you search for not repeat string.

If you know password, use something like this

cat data.txt | grep 'password'

If you don`t know the password and this password is only unique line in file you must create a script. For example in Python

file = open("data.txt","r")
f = file.read()
for line in f: 
   if 'pass' in line:
        print pass

Of course replace pass with something else. For example some slice from line.