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Vim Buffers and Text-buffer Execution

VIM distinguishes between windows and buffers. Buffer is a memory space with some file. Window is a part of some buffer (or all the buffer) displayed on the screen. Such a logical approach is an important advantage of all orthodox editors that provides additional flexibility. 

The topic, which is often glossed over or omitted entirely in most proprietary 'vi' documentation, can be stated very simply: any named text buffer can be treated as a 'vi' command-mode macro by typing the at-sign character ("@") followed by the name of the buffer. If named buffer "a" contains H!Lsort then "@a" from 'vi' command mode will sort the lines now on the terminal screen.

The same would of course be true of a "map" that said the same thing; this example is for illustration. The ability to execute a named text buffer as if the buffer were a sequence of commands allows 'vi' macros sometimes to operate in a self-modifying way, because a macro can load a text buffer from text in the current file and then invoke that text buffer as a command macro, without having to know in advance what the text is that will be loaded into the buffer.

Using hidden buffers

A hidden buffer is not displayed in a window, but is still loaded into memory. This makes it possible to jump from file to file, without the need to read or write the file every time you get another buffer in a window.

If the option 'hidden' ('hid') is set, abandoned buffers are kept for all commands that start editing another file: ":edit", ":next", ":tag", etc.  The commands that move through the buffer list sometimes make the current buffer hidden although the 'hidden' option is not set.  This happens when a buffer is modified, but is forced (with '!') to be removed from a window, and 'autowrite' is off or the buffer can't be written.

You can make a hidden buffer not hidden by starting to edit it with any command.  Or by deleting it with the ":bdelete" command.

When you try to quit Vim while there is a hidden, modified buffer, you will get an error message and Vim will make that buffer the current buffer.  You can then decide to write this buffer (":wq") or quit without writing (":q!"). Be careful: there may be more hidden, modified buffers! :files  

:buffers :ls Show all buffers.  Example:

1 #h "/test/text" line 1
2 - "asdf" line 0
3 % + "version.c" line 1

Each buffer has a unique number.  That number will not change, so you can always go to a specific buffer with ":buffer N" or "N CTRL-^", where N is the buffer number. '-' indicates a buffer that is not loaded.  'h' indicates a hidden buffer: It is loaded, but currently not displayed in a window.  '%' indicates the buffer in the current window.  '#' indicates the alternate buffer for ":e #" or CTRL-^.  '+' indicates a modified buffer. 

:bad[d] [+lnum] {fname} Add file name {fname} to the buffer list, without loading it. If "lnum" is specified, the cursor will be positioned at that line when the buffer is first entered. Note that other commands after the + will be ignored.

:[N]bd[elete] :bd[elete] [N] Unload buffer [N] (default: current buffer) and delete it from the buffer list.  If the buffer was changed, this fails.  The file remains unaffected.  Any windows for this buffer are closed.  If buffer [N] is the current buffer, another buffer will be displayed instead.  This is the most recent entry in the jump list that points into a loaded buffer.

  :[N]bdelete! :bdelete! [N] Unload buffer [N] (default: current buffer) and delete it from the buffer list.  If the buffer was changed the changes are lost.  The file remains unaffected.  Any windows for this buffer are closed.  If buffer [N] is the current buffer, another buffer will be displayed instead.  This is the most recent entry in the jump list that points into a loaded buffer.

:bdelete[!] {bufname} Like ":bdelete[!] [N]", but buffer given by name.  Note that a buffer whose name is a number cannot be referenced by that name; use the buffer number instead.  Insert a backslash before a space in a buffer name.

:N,Mbdelete[!] do ":bdelete[!]" for all buffers in the range N to M (inclusive).

:bdelete[!] N1 N2 ... do ":bdelete[!]" for buffer N1, N2, etc.  The arguments can be buffer numbers or buffer names (but not buffer names that are a number).  Insert a backslash before a space in a buffer name. :[N]bun[load] :bun[load] [N] Unload buffer [N] (default: current buffer).  The memory allocated for this buffer will be freed.  The buffer remains in the buffer list.  If the buffer was changed, this fails. Any windows for this buffer are closed.  If buffer [N] is the current buffer, another buffer will be displayed instead.
This is the most recent entry in the jump list that points into a loaded buffer.

:[N]bunload! :bunload!   The memory allocated for this buffer will be freed.  The buffer remains in the buffer list.  If the buffer was changed, the changes are lost.  Any windows for this buffer are closed.  If buffer [N] is the current buffer, another buffer will be displayed instead.  This is the most recent entry in the jump list that points into a loaded buffer.

:bunload[!] {bufname} Like ":bunload[!] [N]", but buffer given by name.  Note that a buffer whose name is a number cannot be referenced by that name; use the buffer number instead.  Insert a backslash before a space in a buffer name.

:N,Mbunload[!] do ":bunload[!]" for all buffers in the range N to M (inclusive).

:bunload[!] N1 N2 ... do ":bunload[!]" for buffer N1, N2, etc.  The arguments can be buffer numbers or buffer names (but not buffer names that are a number).  Insert a backslash before a space in a buffer name.

:[N]b[uffer][!] [N] Edit buffer [N] from the buffer list.  If [N] is not given, the current buffer remains being edited.  See |:buffer-!| for[!].

:[N]b[uffer][!] {filename}Edit buffer for {filename} from the buffer list.  See |:buffer-!| for [!].  Split window and edit buffer [N] from the buffer list.  If [N] is not given, the current buffer is edited.  Respects the "useopen" setting of 'switchbuf' when splitting.

:[N]sb[uffer] {filename} Split window and edit buffer for {filename} from the buffer list.


:[N]bn[ext][!] [N] Go to [N]th next buffer in buffer list.  [N] defaults to one. Wraps around the end of the buffer list.  See |:buffer-!| for
[!]. If you are in a help buffer, this takes you to the next help buffer (if there is one). Similarly, if you are in a normal (non-help) buffer, this takes you to the next normal buffer. This is so that if you have invoked help, it doesn't get in the way when you're browsing code/text buffers. The next three commands also work like this.

:[N]sbn[ext] [N] Split window and go to [N]th next buffer in buffer list. Wraps around the end of the buffer list. Uses 'switchbuf'

:[N]bN[ext][!] [N] :[N]bp[revious][!] [N] Go to [N]th previous buffer in buffer list.  [N] defaults to one.  Wraps around the start of the buffer list.  See |:buffer-!| for [!] and 'switchbuf'.

:[N]sbN[ext] [N] :[N]sbp[revious] [N] Split window and go to [N]th previous buffer in buffer list. + Wraps around the start of the buffer list. Uses 'switchbuf'.

:br[ewind][!] Go to first buffer in buffer list.  See |:buffer-!| for [!].

:sbr[ewind] Split window and go to first buffer in buffer list. Respects 'switchbuf' option.

:bl[ast][!] Go to last buffer in buffer list.  See |:buffer-!| for [!].

:sbl[ast] Split window and go to last buffer in buffer list. Respects 'switchbuf' option.

:[N]bm[odified][!] [N] Go to [N]th next modified buffer in buffer list.

:[N]sbm[odified] [N] Split window and go to [N]th next modified buffer in buffer list.  Respects 'switchbuf' option.

:[N]unh[ide] [N] :[N]sun[hide] [N] Rearrange the screen to open one window for each loaded buffer in the buffer list.  When a count is given, this is the maximum number of windows to open.

:[N]ba[ll] [N] :[N]sba[ll] [N] Rearrange the screen to open one window for each buffer in the buffer list.  When a count is given, this is the maximum
number of windows to open.  Buf/Win Enter/Leave autocommands are not executed for the new windows here, that's only done
when they are really entered.

Note: All the commands above that start editing another buffer, keep the 'readonly' flag as it was.  This differs from the ":edit" command, which sets the 'readonly' flag each time the file is read.