Question 112428 in Ubuntu Question posted in
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Ubuntu – get the lines added to a file, and th lines deleted from a file in separate files

i have two different txt files. The first one is the source file. The second file file b is the same file, but after some edits. New lines have been added, and some lines from file A have been deleted . Our task is to get in two new separate files the lines that have been added to file a, and in a new file the lines that have been removed from file a

a.txt

    Common
    Common
    A-ONLY
    Common

b.txt

    Common
    B-ONLY
    Common
    Common

I need as output in a separate new file to show lines removed from a.txt

output:

    A-ONLY

I then need as in a separate new file output to show lines added to a.txt

output:

    B-ONLY

How can i do it with ubuntu linux commands with sed or awk? do i first need to sort the files i compare?

Tags:

2

Answers


  1. 0

    Assuming the files can be sorted before comparison:

    $ comm -23 <(sort a.txt) <(sort b.txt)
A-ONLY

$ comm -13 <(sort a.txt) <(sort b.txt)
B-ONLY
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  2. 0

    With GNU diff:

    $ diff --unchanged-line-format= --new-line-format= a.txt b.txt
A-ONLY

    $ diff --unchanged-line-format= --old-line-format= a.txt b.txt
B-ONLY

    With standard diff and awk:

    $ diff -u a.txt b.txt | awk 'NR>2 && sub(/^[-]/,"")'
A-ONLY

    $ diff -u a.txt b.txt | awk 'NR>2 && sub(/^[+]/,"")'
B-ONLY

    It is probably possible to implement with awk alone but you would just be trying to re-invent diff.

    With standard diff and sed:

    $ diff -u a.txt b.txt | sed -n '3,$s/^-//p'
A-ONLY

    $ diff -u a.txt b.txt | sed -n '3,$s/^+//p'
B-ONLY

    It’s probably very difficult to implement with sed alone, if it is even possible.

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