------------------------------------------------------------------------
rows <-> columns
------------------------------------------------------------------------

Say you have a row of numbers. 
$ echo {01..09}
01 02 03 04 05 06 07 08 09

It is easy to convert this to a column
$ echo {01..09} | xargs -n 1
01
02
03
04
05
06
07
08
09

Consider the opposite case where you have a column
$ seq 9
1
2
3
4
5
6
7
8
9

The simplest way to convert this to a row is
$ seq 10 | column

To convert to a row you a choice of delimeters (-d; but limited
to one character)

$ seq 9 | paste -s -d " " -      %pretty clever (not discovered by me)
$ paste -s -d " " <(seq 9)   
1 2 3 4 5 6 7 8 9

$ seq 9 | sed -n '1h;1!H;${x;s/\n/,/gp;}'   %comma-separated
1,2,3,4,5,6,7,8,9

$ ifs=":"                           %you can set the field separator
$ seq 9 | sed -n '1h;1!H;${x;s/\n/'$ifs'/gp;}' 
1:2:3:4:5:6:7:8:9

------------------------------------------------------------------------
An unorthodox solution
------------------------------------------------------------------------
This solution makes use of the faca that command substitution gobbles up
"\n".

$ echo $(seq 5)
1 2 3 4 5 


$ seq 5 > a
$ cat a
1
2
3
4
5

$ echo $(cat a)
1 2 3 4 5

$ cat b
1 a
2 b
3 c
4 d
5 e

$ echo $(cat b)
1 a 2 b 3 c 4 d 5 e