Shell line command Sorting command

Question

I have a Masters.txt (all records) and a New.txt file. I want to process New.txt against Masters.txt and output all the lines from New.txt that do not exist in Masters.txt

i'm not sure if this is something the sort -u command can do.

Possible duplicate: http://stackoverflow.com/q/5812756/576875 — Arnaud Le Blanc, Sep 05 '11 at 20:02

score 2 · Answer 1 · answered Sep 05 '11 at 19:54

2

Sort both files first using sort and then use the comm command to list the lines that exist only in new.txt and not in masters.txt. Something like:

sort masters.txt >masters_sorted.txt
sort new.txt >new_sorted.txt
comm -2 -3 new_sorted.txt masters_sorted.txt

comm produces three columns in its output by default; column 1 contains lines unique to the first file, column 2 contains lines unique to the second file; column 3 contains lines common to both files. The -2 -3 switches suppress the second and third columns.

answered Sep 05 '11 at 19:54

Tamás

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shouldnt it be something like comm -2 -3 new_sorted.txt masters_sorted.txt > new.txt – acctman Sep 05 '11 at 22:14
Well, if you want to store the result in ``new.txt`` (losing the contents of the old one), then yes, it should. – Tamás Sep 05 '11 at 22:16
hmm is there a file list item limit... it doesn't seem to be work at. no output and not changes in either file – acctman Sep 05 '11 at 22:46
1

You don't need the temp files: `comm -23 <(sort masters.txt) <(sort new.ext)` – glenn jackman Sep 06 '11 at 11:07

score 0 · Answer 2 · answered Sep 05 '11 at 19:54

0

see the linux comm command:

http://unstableme.blogspot.com/2009/08/linux-comm-command-brief-tutorial.html

answered Sep 05 '11 at 19:54

momeara

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Shell line command Sorting command

2 Answers2