join every 2 lines in a file

http://www.theunixschool.com/2012/03/join-every-2-lines-in-file.html


훌륭하다 훌륭해.
$ paste - - -d, < file
$ paste -s -d",\n" file
$ sed 'N;s/\n/,/' file
$ perl -pne 'if($.%2){s/\n/,/;}' file
$ xargs -L 2 < file | awk '$1=$1' OFS=,
$ awk 'NR%2{printf "%s,",$0;next}{print;}' file