行转列(awk):

awk -F "+" '{for(i=1;i<=NF;i++) a[i,NR]=$i}END{for(i=1;i<=NF;i++) {for(j=1;j<=NR;j++) printf a[i,j] " ";print ""}}' file.txt


列转行(tr):

cat file.txt |tr "\n" ","|sed -e 's/,$/\n/'