Using Grep in bash

Hi,

I have two files (ASCII text), pass.old and pass.new, I want to find all the lines in pass.new which don't appear in pass.old (most lines overlap)... here's what I've got so far:

sort -n pass.old pass.new | uniq -u

that prints the lines in pass.new which don't appear in pass.old (but also the ones in pass.old which don't appear in pass.new), I want the output to be only the ones which appear in pass.new and not pass.old, I recon it'll be something to do with grep.

I've tried a few things like:

grep (sort -n pass.old pass.new | uniq -u) pass.new
or grep [sort -n pass.old pass.new | uniq -u] pass.new

I always get error messages, and I'm not quite sure how to write it so that it does grep of the output of sort -n etc. on pass.new,

Hopefully that made sense,

Any help/ideas on this one?

why not use use diff?

Code:

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diff pass.new pass.old

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Code:

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grep -v -F -f pass.old pass.new

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Quote:

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Originally Posted by steeldriver

why not use use diff?

Code:

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diff pass.new pass.old

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Two reasons, firstly the lines have to be in the same order for diff to print the lines in 1 which aren't in the other, (although in this case they were, but I'm also interested in a more general method for doing it incase I come across similar problems in the future).

Also diff prints the different output from both files (although to be fair it does specify which file each line came from),

Not a bad shout, though, and cheers for the input.

Quote:

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Originally Posted by diesch

Code:

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grep -v -F -f pass.old pass.new

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Worked nicely. Cheers.

Also, as a side thing, is it possible to do what I was trying to do earlier somehow?

i.e. do: grep [output of: sort -n pass.new pass.old | uniq -u] pass.new

(so it prints the matches of each outputted line from: sort -n pass.new pass.old | uniq -u with file pass.new)?

if you want to embed a command you need $() not ()

this should sorta work

Code:

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grep -E "^("$( sort pass.* | uniq -u | tr '\n' '|' )"$)$" pass.new

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