Turning multiple lines into one comma separated line

Question

I have the following data in multiple lines:

foo
bar
qux
zuu
sdf
sdfasdf

What I want to do is to convert them to one comma separated line:

foo,bar,qux,zuu,sdf,sdfasdf

What's the best unix one-liner to do that?

If the solutions below do not produce the required results, e.g. only the last line's content showing, you may have unwanted control characters in your input, e.g. `\r`. You can check that by piping the input to `hd` or `hexdump`. `\r` will (in conjunction with `\n`) produce the two-byte sequences `0a0d`. Fix with `|sed 's/\r//g'`. — valid, Oct 20 '14 at 15:57
This question is a duplicate, but not all of the answers are. — reinierpost, Oct 30 '14 at 10:41

score 178 · Accepted Answer · answered Apr 02 '13 at 08:04

178

Using paste command:

paste -d, -s file

answered Apr 02 '13 at 08:04

Guru

16,456
2
33
46

11

But how to accomplish that for a variable or a pipe? Update myself: Using -s without value .... | paste -d, -s – NeoMorfeo Oct 28 '15 at 14:37
2

While this works for when one wants to convert newlines (`\n`) into commas, it seems that one cannot use this method if one needs to convert newlines into "`, `" which is required for many other commands. – CoderGuy123 Jul 27 '16 at 03:48
7

@NeoMorfeo You can use a `-` to read from pipe as well. Ex: `echo -e "1\n2\n3" | paste -d, -s -` – Carson Anderson Feb 06 '17 at 23:58

score 92 · Answer 2 · answered Jul 20 '13 at 06:47

92

file

aaa
bbb
ccc
ddd

xargs

cat file | xargs

result

aaa bbb ccc ddd

xargs improoved

cat file | xargs | sed -e 's/ /,/g'

result

aaa,bbb,ccc,ddd

answered Jul 20 '13 at 06:47

Serhii Kuzmychov

1,186
8
10

1

xargs turns multi-line into one line space-separated, then sed replaces all space by ','(or ' ,' if you will use sed -e 's/ /\ ,/g' ( by the way -e can be omited) – Serhii Kuzmychov Aug 24 '13 at 14:11
usually xargs is not intended for t but it works :) – Serhii Kuzmychov Aug 24 '13 at 14:17
and it more prefer way for every day use insted of the one bellow – Serhii Kuzmychov Aug 24 '13 at 14:19
Thanks for the step by step! I had a file with one entry per line, (fn, ln,id,status, blank line.) I needed it in CSV, so I swapped "blank line" with an unused symbol (sed -e 's/^$/#/') before using the mod you've explained. – Bee Kay Oct 31 '16 at 19:34
I found this to be the solution I was looking for, not the accepted one because it works for pipes and multiple files and you can pass it to tr -s " " "\t" if you want to add tabs and so forth. Thank you. – jimh Sep 05 '17 at 00:45

score 12 · Answer 3 · edited Apr 02 '13 at 12:34

12

There are many ways it can be achieved. The tool you use mostly depends on your own preference or experience.

Using tr command:

tr '\n' ',' < somefile

Using awk:

awk -F'\n' '{if(NR == 1) {printf $0} else {printf ","$0}}' somefile

edited Apr 02 '13 at 12:34

Chris Seymour

83,387
30
160
202

answered Apr 02 '13 at 08:14

n3rV3

1,096
8
10

1

your both commands would generate ending comma – Kent Apr 02 '13 at 08:21
yes, i can fix it in awk but not in tr, give me a min. – n3rV3 Apr 02 '13 at 08:39
2

`awk '{printf NR==1?$0:","$0}' file` – Chris Seymour Apr 02 '13 at 12:32
13

Never use `printf $0` as it will fail cryptically if $0 contains any printf formatting characters. The synopsis for printf is `printf format, data` so use `printf "%s", $0` instead. – Ed Morton Apr 02 '13 at 14:10
i still have a lot to learn. thanks – n3rV3 Apr 02 '13 at 18:10

score 10 · Answer 4 · edited Mar 26 '19 at 22:28

10

xargs -a your_file | sed 's/ /,/g'

This is a shorter way.

edited Mar 26 '19 at 22:28

chrlaura

1,307
1
9
11

answered Aug 24 '13 at 14:23

Serhii Kuzmychov

1,186
8
10

2

except if there are spaces in your lines... – cadrian Aug 26 '16 at 13:52
sed -e 's/ /+/g' test |xargs|sed 's/ /,/g;s/+/ /g' it was just an idea how to use xargs :) do not think it is seriously – Serhii Kuzmychov Sep 03 '16 at 19:59

score 8 · Answer 5 · answered Apr 02 '13 at 08:20

8

based on your input example, this awk line works. (without trailing comma)

awk -vRS="" -vOFS=',' '$1=$1' file

test:

kent$  echo "foo
bar
qux
zuu
sdf
sdfasdf"|awk -vRS="" -vOFS=',' '$1=$1' 
foo,bar,qux,zuu,sdf,sdfasdf

answered Apr 02 '13 at 08:20

Kent

189,393
32
233
301

You only need to use `-v` if you want the variables available in the BEGIN block, slightly more concise `awk '$1=$1' RS= OFS=, file`. – Chris Seymour Apr 02 '13 at 12:31
3

For clarity and to avoid getting surprised when you later do try to use a variable in a BEGIN block, I'd always use -v unless setting a variable to different values between files. FYI omitting the space between -v and the variable name makes your script un-necessarily gawk-specific so I'd use `-v RS=` instead of `-vRS=`. – Ed Morton Apr 02 '13 at 14:13
@EdMorton thx for the comment. (the "space" between -v and va). I learned many tips from you :). Personally I always use `-v` too. – Kent Apr 02 '13 at 14:22

choroba · Answer 6 · 2013-04-02T09:41:33.367

6

Perl one-liner:

perl -pe'chomp, s/$/,/ unless eof' file

or, if you want to be more cryptic:

perl '-peeof||chomp&&s/$/,/' file

edited Apr 02 '13 at 09:41

answered Apr 02 '13 at 08:15

choroba

231,213
25
204
289

5

Even more cryptic: `perl '-peeof||s|$/$|,|' file` – sid_com Apr 02 '13 at 11:00
1

sid_com, I like your choice of substitution delimiters :D... `perl -pe 'eof or s#\n$#,#' thing` – protist May 30 '13 at 05:43
ok, even more cryptic perl: perl -l54 -pe 'eof and $\=""' file (and you can go with empty script body if you can tolerate last coma) – Peter K Aug 06 '14 at 16:58

score 2 · Answer 7 · answered May 29 '13 at 18:38

2

sed -n 's/.*/&,/;H;$x;$s/,\n/,/g;$s/\n\(.*\)/\1/;$s/\(.*\),/\1/;$p'

answered May 29 '13 at 18:38

protist

1,172
7
9

1

too complicated. Please explain @protist. – Lazarus Thurston Aug 26 '17 at 14:13

Vijay · Answer 8 · 2014-08-07T06:32:41.430

1

perl -pi.bak -e 'unless(eof){s/\n/,/g}' your_file

This will create a backup of original file with an extension of .bak and then modifies the original file

edited Aug 07 '14 at 06:32

answered Apr 02 '13 at 10:19

Vijay

65,327
90
227
319

Turning multiple lines into one comma separated line

8 Answers8

file

xargs

result

xargs improoved

result

Linked