How to remove duplicate words from a plain text fi

Question

I have a plain text file with words, which are separated by comma, for example:

word1, word2, word3, word2, word4, word5, word 3, word6, word7, word3

i want to delete the duplicates and to become:

word1, word2, word3, word4, word5, word6, word7

Any Ideas? I think, egrep can help me, but i'm not sure, how to use it exactly....

Answer 1

Creating a unique list is pretty easy thanks to uniq, although most Unix commands like one entry per line instead of a comma-separated list, so we have to start by converting it to that:

$ sed 's/, /\n/g' filename | sort | uniq
word1
word2
word3
word4
word5
word6
word7

The harder part is putting this on one line again with commas as separators and not terminators. I used a perl one-liner to do this, but if someone has something more idiomatic, please edit me. :)

$ sed 's/, /\n/g' filename | sort | uniq | perl -e '@a = <>; chomp @a; print((join ", ", @a), "\n")'
word1, word2, word3, word4, word5, word6, word7

Answer 2

And don't forget the -c option for the uniq utility if you're interested in getting a count of the words as well.

Answer 3

Assuming that the words are one per line, and the file is already sorted:

uniq filename

If the file's not sorted:

sort filename | uniq

If they're not one per line, and you don't mind them being one per line:

tr -s [:space:] \\n < filename | sort | uniq

That doesn't remove punctuation, though, so maybe you want:

tr -s [:space:][:punct:] \\n < filename | sort | uniq

But that removes the hyphen from hyphenated words. "man tr" for more options.

Answer 4

Came across this thread while trying to solve much the same problem. I had concatenated several files containing passwords, so naturally there were a lot of doubles. Also, many non-standard characters. I didn't really need them sorted, but it seemed that was gonna be necessary for uniq.

I tried:

sort /Users/me/Documents/file.txt | uniq -u
sort: string comparison failed: Illegal byte sequence
sort: Set LC_ALL='C' to work around the problem.
sort: The strings compared were `t\203tonnement' and `t\203tonner'

Tried:

sort -u /Users/me/Documents/file.txt >> /Users/me/Documents/file2.txt
sort: string comparison failed: Illegal byte sequence
sort: Set LC_ALL='C' to work around the problem.
sort: The strings compared were `t\203tonnement' and `t\203tonner'.

And even tried passing it through cat first, just so I could see if we were getting a proper input.

cat /Users/me/Documents/file.txt | sort | uniq -u > /Users/me/Documents/file2.txt
sort: string comparison failed: Illegal byte sequence
sort: Set LC_ALL='C' to work around the problem.
sort: The strings compared were `zon\351s' and `zoologie'.

I'm not sure what's happening. The strings "t\203tonnement" and "t\203tonner" aren't found in the file, though "t/203" and "tonnement" are found, but on separate, non-adjoining lines. Same with "zon\351s".

What finally worked for me was:

awk '!x[$0]++' /Users/me/Documents/file.txt > /Users/me/Documents/file2.txt

It also preserved words whose only difference was case, which is what I wanted. I didn't need the list sorted, so it was fine that it wasn't.

Answer 5

ruby -pi.bak -e '$_.split(",").uniq.join(",")' filename ?

I'll admit the two kinds of quotations are ugly.

Answer 6

Here's an awk script that will leave each line in tact, only removing the duplicate words:

BEGIN { 
     FS=", " 
} 
{ 
    for (i=1; i <= NF; i++) 
        used[$i] = 1
    for (x in used)
        printf "%s, ",x
    printf "\n"
    split("", used)
}