ctrl-6

Demo

For the example we will create 3 new temp files and then open them in vim.

touch vim_test1.txt
touch vim_test2.txt
touch vim_test3.txt
vim vim_test*

From with in vim

:ls 
1 %a   "vim_test1.txt"                line 2
2      "vim_test2.txt"                line 0
3      "vim_test3.txt"                line 0

Buffer 1 is active (%a) if we jump to buffer 3

:b3
:ls
1 #    "vim_test1.txt"                line 2
2      "vim_test2.txt"                line 0
3 %a   "vim_test3.txt"                line 2

Buffer 3 is active (%a) and 3 is previous edited buffer. ctrl-6 will switch these around. Toggling the active buffer between the two.

ctrl-6
:ls
1 %a   "vim_test1.txt"                line 2
2      "vim_test2.txt"                line 0
3 #    "vim_test3.txt"                line 2 
ctrl-6
:ls
1 #    "vim_test1.txt"                line 2
2      "vim_test2.txt"                line 0
3 %a   "vim_test3.txt"                line 2

To scroll through the buffers in order:

:bn (Next Buffer)
:bp (Previous Buffer)