Changing delimiter of the uniq command

Question

I'd like the output of the uniq command to be comma separated, so that instead of:

     30 hello
     31 world
     36 hey_there
    142 i_am_bigest

I'll get:

30,hello
31,world
36,hey_there
142,i_am_biggest

My input has no spaces, but just using sed or tr can be a problem since the number of leading spaces varies according to the number of decimal digits in the count.

This Q. specifically looks like changing the output of `... | sort -rn | uniq -c`. — agc, Jan 16 '19 at 19:44

score 21 · Accepted Answer · answered Jun 10 '13 at 06:13

21

Pipe the output to

sed -e 's/^ *//;s/ /,/'

This first removes the leading spaces (^ *) then replaces the first space with a comma.

answered Jun 10 '13 at 06:13

nneonneo

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Jonathan Leffler · Answer 2 · 2013-06-10T06:45:38.423

man uniq (at least on Mac OS X, aka BSD) does not give any way to handle that. Your best bet is probably sed:

... |
uniq -c |
sed 's/^ *\([0-9][0-9]*\) /\1,/'

The output from uniq -c consists of some blanks, a number, a blank, and the input string.

The basic idea is that the sed script looks for an arbitrary number of blanks, a number and a blank, and replace it by the number and a comma. Looking at the POSIX specification for uniq, the output is not supposed to have leading blanks (the printf() format should be "%d %s"), but leading blanks are normal in practice (for small enough repeat counts; on Mac OS X, the output printf() format is effectively "%5d %s").

score 1 · Answer 3 · answered Jun 10 '13 at 06:23

1

pipe the output to :

perl -lane '{print join ",", @F}'

answered Jun 10 '13 at 06:23

Vijay

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As with the `awk`-based solution, this does not work well when the input lines have multiple fields according to Perl. For example, with sorted input consisting of 4 lines containing `aaa aaa aaa aaa` and 5 lines containing `aba aba aba aba`, the ouptut from your script (after `sort` and `uniq -c`) is two lines: `4,aaa,aaa,aaa,aaa` and `5,aba,aba,aba,aba`; note the extra (and unwanted) commas. – Jonathan Leffler Jun 10 '13 at 06:43

score 1 · Answer 4 · answered Jan 16 '19 at 19:41

1

Using printf works:
```
xargs -L 1 printf '%s,%s\n' < file
```
Using bash:
```
printf '%s,%s\n' $(<file)
```

In a POSIX shell this would also work:

printf '%s,%s\n' $( ...various commands... | uniq -c )

answered Jan 16 '19 at 19:41

agc

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score 0 · Answer 5 · answered Apr 10 '21 at 15:51

0

Using @nneonneo's answer, I wrote this function and added it to my .bashrc:

uniqc(){
    uniq -c |sed -e 's/^ *//;s/ /,/' 
}

Usage, instead of doSomething | uniq -c, do:

doSomething | uniqc

answered Apr 10 '21 at 15:51

Isin Altinkaya

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Changing delimiter of the uniq command

5 Answers5