Regain commands syntax:

REGAIN [profile][/option][/option]...[//special_option][//special_option]...
Special options operate on the resident copy of REGAIN
REGAIN //    removes the resident copy
REGAIN //-   suspends operation but leaves the resident copy in memory
REGAIN //+   resumes operation of the resident copy
REGAIN //G1  filespec gets commands for command.com's stack from filespec
REGAIN //P1  filespec puts commands from command.com's stack to filespec
Other special options are G2 & P2 for the 2nd stack and PA for aliases

REGAIN ?  for help

Options:
Specify key assignments: Name, 0(if extended key code), key #
Name     Default key      Name      Default key      Name      Default key
MTAB     Shift-tab        DEOL      Ctrl-end         BKSPC2    Backspace
NCHR     Cursor right     DBOL      Ctrl-home        TOGLINS   Ins
PCHR     Cursor left      PSTK      Cursor up        DSPALIAS  Ctrl-A
MBOL     Home             NSTK      Cursor down      SETSTACK  PgUp
MEOL     End              DSTK      Ctrl-PgDn        RESSTACK  PgDn
MEOL2    End              CSTK      Ctrl-PgUp        EDTALIAS  Ctrl-E
PWORD    Ctrl-left        DLINE     Esc              SETCMDBF  Ctrl-D
NWORD    Ctrl-right       ENTER     Enter            SETCMDB2  Ctrl-G
FINDCHR  Ctrl-F           ENTER2    Enter            KEEPLINE  Ctrl-K
DCHR     Del              FINDNEXT  Ctrl-N           FINDPREV  Ctrl-B
DWORD    Ctrl-X           BKSPC     Backspace        TOGLWNDW  Ctrl-W
VIEWALI  Ctrl-V           AUTOWNDW  Ctrl-T           RESETINS  Ctrl-Q
OTHRSTAK Ctrl-O           RSOLVALI  Ctrl-R           RSOLVABR  Ctrl-Y
FNSHNAME Ctrl-L           USURPLIN  Ctrl-U
 
             * * * * * *   Controls     * * * * * * *
 
APPNDPRO 0,(1)  Drop current definitions or add to them.
WNDW     1,(0)  Automatically display window or not.
WNDWCNTL 1,(0)  Enable number & sign keys to control window or not.
MINSAV   n      Save commands of length n or greater on stack.
SAVALL   1(0)   Save commands on stack even if retrieved from stack or not.
SAVPFK   2(0)(1)Save pf strings on stack, or not, or only if no cr.
PFCRCHR  ~      Define command separator character.
KEYINCR  `      Define KEYIN command separator character.
NOALIAS  !      Define NO ALIAS symbol.
ANESTING 10     Set maximum levels of alias nesting 0 TO 254.
NBRSYMBL ^      Specify number symbol.
QUERYSYM ?      Specify search command as "?".
EXECSYM  61     Specify search & execute command as "=".
EXEC3F   1,(0)  Perform DOS function 3F, or not.
RESERVE  n      Reserve n bytes to add alias/pf's (only on 1st invocation).
STK1SIZ  n      n bytes for dos commands. (only on 1st invocation).
STK2SIZ  n      n bytes for non-dos commands. (only on 1st invocation).
CMDSIZ   n      n bytes for resident commands.(only on 1st invocation).
BATSIZ   n      n bytes to store batch commands.(only on 1st invocation).
BATCHR   %      Define variable substitution character.
WNDOWCOL 36     Set left edge of window.
WWIDTH   40     Set window width.
WNDOWROW 3      Set top edge of window.
WHEIGHT  12     Set window height.
WDIRECT  1(0)   Write window directly to video buffer.
VIDATRIB 0      Window video attribute for color - Use current attribute if 0.
VIDRATRB 112    Attribute for reverse video.
MONATRIB 0      Window video attribute for monochrome.
MONRATRB 112    Attribute for reverse video.
WTRUNC   1(0)   Truncate lines in window.
SHOWIT   0(1)   Display aliases at installation time or not.
ECHOOFF  0(1,2) Display all multiple commands or not, 2=no - line feed.
PFECHOFF 0(1,2) Display all PF lines or not.
LOCKINS  0(1)   Normal toggle or set with insert key, reset with Ctrl-Q.
INSERTON 0(1)   Set default state of insert function. 0=off.
BKSPCNTL 0(1)   Back space - delete (blank if 0) previous chr when insert on.
CURSOR   7,11   Set default cursor shape for mono,color.
SETCURSR  0(1)  Set cursor size automatically or to REPCURSR and INSCURSR.
REPCURSR  11,12 Replace mode cursor fills 11th to 12th lines of character box.
INSCURSR  6,12  Insert mode cursor fills 6th to 12th lines of character box.
FRAME-ES 205,186,201,187,188,200,62,61 characters for window display.
EGACURSR 0(1)   Assume cursor size for mono/CGA or handle EGA/VGA properly.
STDIO    2(1,0) Display goes to std error device or std output device or
                DOS character display.
ABBREV   1(0)   Substitute abbreviations from environment strings or not.
ESCAPE   0(1)   If 1, clear screen on 2nd tap on Esc key.
FILATRIB 16     Attribute to use for filename finishing
                +2=hidden,+4=system,+16=directories,+8=vol.label
PROTRCAL 0(1,2,3) Protect against accidental stack recall. 0= off,
                  1=lock, 2= keep temporarily, 3= keep permanently, then recall.
TITLE1   Primary   Specifies the window title at the DOS prompt.
TITLE2   Secondary Specifies the window title when not at the DOS prompt.
TITLEA   Aliases   Specifies the alias window title.
 
  Key(default)     Usage
 
  Right arrow      Advances the cursor one character position.
  Left arrow       Backs up the cursor one character position.
  Ctrl-Right       Advances the cursor to the next word.
  Ctrl-Left        Backs up the cursor to the previous word.
  Left shift-Tab   Backs up the cursor to the previous tab position.
  Right shift Tab  Advances the cursor to the next tab position.
  Home             Moves the cursor to the beginning of the line.
  End              Moves the cursor to the end of the line.
  Del              Erases the character at the cursor position.
  Back Space       Erases the character to left of the cursor.
  Esc              Erases the entire line.
    w/left shift   also moves the cursor down 1 line.
    w/right shift  also moves the cursor up 1 line.
  Ctrl-Home        Erases from the beginning of the line to the cursor.
  Ctrl-end         Erases from the cursor to the end of the line.
  Up arrow         Recalls the previous instruction from the stack.
  Down arrow       Recalls the following instruction from the stack.
  Ctrl-PgUp        Clears the current stack of all entries.
  Ctrl-PgDn        Erases the currently displayed stack entry.
  Ins              Toggles insert mode. If active, the cursor size changes.
  Ctrl-A           Displays alias list and resident commands.
  Ctrl-B           Move cursor to previous current character.
  Ctrl-D           Identify present caller as command.com.
  Ctrl-E           Edit alias or pf phrase.
  Ctrl-F           Move cursor to next character typed.
  Ctrl-G           Same as Ctrl-D above for a 2nd caller.
  Ctrl-K           Keep (save) line being edited on stack.
  Ctrl-L           Finish typing filename.ext
  Ctrl-N           Move cursor to next current character.
  Ctrl-O           Fix cursor size (reset to profile's value).
  Ctrl-Q           Reset insert mode.
  Crtl-R           Resolve the alias on the current line.
  Ctrl-T           Toggle auto window display.
  Ctrl-U           Usurp screen line.
  Ctrl-V           View aliases in window.
  Ctrl-W           Toggle window display of stack.
  Ctrl-X           Delete the current word.
  Ctrl-Z           End of file marker (1AH). Replaces the F6 key.
 
 While window is displayed:
  Enter            Executes current command or returns alias for editing.
  Esc              Exits window to previous line.
  Ctrl-U/W/V       Returns current line for editing.
  Left/right arrow Move text latterally within the window.
  Tab, tab/shift    "    "       "       "      "    "
  Ctrl/left/right   "    "       "       "      "    "
  Up/down arrows   Select current line.
  Home             Moves last line entered to top.
  End              Moves first line entered to top.
  Ctrl-PgUp        Clears the current stack of all entries.
  Ctrl-PgDn        Erases the currently displayed stack entry.
  Use number pad keys with shift or Num Lock: (if enabled)
  2/4/6/8          Moves window 1 row/column around the screen.
  1/3/7/9          Moves window to extreme corners of screen.
  +/-              Grows/shrinks window.
  Any programmed function key:
                   Exits the window, clears the line and activates the key.
 
Search and execute commands:
 ?abc  Returns the most recent line beginning with abc.
 ?ab?d Returns a line beginning with abcd or abxd or ab1d or...
 =abc  Returns the most recent matching line and then executes it.

