Join lines into one line

[Hein van den Heuvel]

I know this horse has been beaten but here is how I would deal with the 'extra comma' problem in awk:

$ awk '{printf comma $0; comma=","}' x.txt

so we print a comma BEFORE each fresh line, but we don't want one on the first line, so we set a symbol to the value comma, after the first print.
(and again and again, but awk don't mind that :-).

fwiw,
Hein

[Jose Mosquera]

Hi,

#AUX=`cat file.txt|tr "\n" ","`
#echo $AUX > file.aux
#cat file.aux
line1,line2,line3,line4,...,

Rgds.

[Viktor Balogh]

Hein,

>so we print a comma BEFORE each fresh line, but we don't want one on the first line

that's exactly what I did with

# awk '!(NR-1) {printf $0} NR-1 {printf ","$0} END {print ""}'

but you solution is genious! Maybe an END section just to echo a linefeed after the last line... ;)