where is the : command history stored?

Question

I want to know where the : command history is stored for a particular vim session. I know we can scroll and search through the history. My objective is to take a portion of the commands that I executed using trial and error and create a vim source file.

Answer 1

it is stored at $HOME/.viminfo

From the vim help command:

The viminfo file is used to store:
- The command line history.
- The search string history.
- The input-line history.
- Contents of registers.
- Marks for several files.
- File marks, pointing to locations in files.
- Last search/substitute pattern (for 'n' and '&').
- The buffer list.
- Global variables.

Answer 2

You can also open your recent command history in a minibuffer using the q: or :<CTRL-F> commands

 OPEN

 There are two ways to open the command-line window:
 1. From Command-line mode, use the key specified with the 'cedit' option.
    The default is CTRL-F when 'compatible' is not set.
 2. From Normal mode, use the "q:", "q/" or "q?" command.  *q:* *q/* *q?*
    This starts editing an Ex command-line ("q:") or search string ("q/" or
    "q?").  Note that this is not possible while recording is in progress (the
    "q" stops recording then).

 When the window opens it is filled with the command-line history.  The last
 line contains the command as typed so far.  The left column will show a
 character that indicates the type of command-line being edited, see
 |cmdwin-char|.

You can move around this window, and copy just like a normal buffer. Hitting <Enter> over a command will execute it.

Answer 3

You are looking for the functions histget(), histadd() and histdel().

EDIT: viminfo file will contain history data from several sessions, which I guess, you were already aware of, according to the way you formulated your question.