\chapter{Glossary Of Obscure TECO Terms}
\label{Glossary Of Obscure TECO Terms}

\begin{description}

     \item[Accent grave]
                    The \escape  character.   Echoed  for  TECO's  text  and
                    command  string delimiter when an ESCape surrogate
                    is  in  effect.   Actually  set  as   the   ESCape
                    surrogate by the 8192 ET bit.

     \item[Abort-on-error bit]
                    The 128's bit of the ET flag.  If this bit is set,
                    then  TECO will abort execution on encountering an
                    error  (after  printing  the  error  message)  and
                    control returns to the operating system.  This bit
                    is initially set when TECO starts up, but is reset
                    whenever TECO issues its prompt.

     \item[{\tt <ALTMODE>}]
		    One  of  several  characters  that   TECO   treats
                    specially for use as a delimiter.  Known as ESCAPE
                    in more recent times, but traditional  TECO  users
                    will still go on ending their command strings with
                    {\tt <ALT><ALT>}.

     \item[Anchored search]
                    A search ({\tt S}) or search and  replace  ({\tt FS})  
			command
                    that is preceded by a {\tt ::}.  This indicates that the
                    search  must  match  the  characters   immediately
                    following  the current pointer position.  If these
                    characters do not match, no further  searching  is
                    performed  and  the  text  buffer pointer does not
                    move.

     \item [Argument pair]
		    A command of the  form  {\tt m,n}  where  {\tt m}  
			and  {\tt n}  are
                    numbers  (or  TECO  commands that return numbers).
                    When used before a command that normally  acts  on
                    lines,  the  argument  pair  causes the command to
                    work on characters.  The characters  specified  by
                    this  argument  pair  is  the  set  of  characters
                    between pointer positions {\tt m} and {\tt n}.  
		The  number  {\tt m}
                    should normally be less than or equal to {\tt n}.

     \item[ASCII  code  ]
		    The  American  Standard  Code   for   Information
                    Interchange.   The  code used by TECO to represent
                    characters internally.   Consult  Appendix  A  for
                    details.

     \item[{\tt @}-sign modified command]
                    A command that is preceded by an {\tt @}-sign modifier.

     \item[{\tt @}-sign modifier]
                    An  at-sign  ({\tt @})  that  proceeds  a  command.   It
                    indicates  to TECO that the string argument to the
                    command  is  to  delimited  on  both  sides  by  a
                    user-supplied   delimiter   rather   than   to  be
                    delimited only at the  end  by  a  TECO-designated
                    delimiter (normally {\tt <ESCAPE>}).

     \item[Automatic refresh]
                    A  refresh  of  the  buffer  display   done   when
                    scrolling  is  active  (when {\tt 7:W} is non-zero) just
                    before TECO issues its asterisk prompt.  Automatic
                    refresh can be disabled by the 128 ED bit.

     \item[Automatic type out]
                    The feature of TECO that causes lines of  text  to
                    be  automatically  typed  out.  The ES flag may be
                    used to control the automatic type  out  of  lines
                    after search commands, and the EV flag may be used
                    to cause automatic type out of lines after command
		    execution.

     \item[Auto-trace mode]
                    A mode that TECO goes into when the 4's bit of the
                    EH  (Help-level)  flag is set.  In this mode, TECO
                    will automatically print out the erroneous command
                    string after an error occurs.

     \item[Backup protection]
                    The process of preserving the user's original file
                    (as  a  backup) when editing that file with the {\tt EB}
                    (Edit with Backup) command.

     \item[Backwards searches]
                    A search that proceeds in the backwards direction.
                    If  the  string being looked for does not occur at
                    the current pointer position, the pointer position
                    is  moved  back  one  character  and the search is
                    tried again.  This continues until the  string  is
                    found or until the boundary of the search has been
                    reached or until the beginning of the current text
                    buffer  has  been  reached.  Backward searches are
                    initiated by using a negative argument to a search
                    command  or  by  using an argument pair {\tt m,n} 
			with {\tt m}
                    greater than {\tt n} to an {\tt FB} or {\tt FC} command.

     \item[Bounded searches]
                    A search command that requires  searching  only  a
                    portion   of   the  text  buffer.   Of  particular
                    importance is the case  where  you  only  want  to
                    search  the  current  line  for  a  given  string.
                    Bounded searches are  accomplished  using  the  {\tt FB}
                    command.

     \item[Case flagging]
		    A mode of TECO wherein, on type out, it will  flag
                    alphabetic  characters  (in  either upper or lower
                    case) by  preceding  them  with  a  single  quote.
                    Lower  case  flagging  is  particularly  useful on
                    terminals that do not display  lower  case.   Case
                    flagging  is  controlled  by  EU,  the  case flag.
                    Setting EU to 0 sets  lower  case  flagging  mode;
                    setting EU to 1 sets upper case flagging mode, and
                    setting EU to -1 removes all case flagging.

     \item[Character-oriented editor]
                    An  editor  that  allows  modification  of  single
                    characters,  so  that  if  just one character of a
                    line is wrong, the entire line does not have to be
                    retyped.   TECO  is  a  character-oriented  editor
                    (although  it  has  a  number  of  facilities  for
                    dealing with text lines, too).

     \item[Colon-modified command]
                    A  command  that  is  preceded  by  a  colon   ({\tt :})
                    modifier.

     \item[Colon-modifier]
                    A colon preceding a TECO command, used to indicate
                    that  the  action  of  the  command  is to change.
                    Frequently indicates that the command is to return
                    a  value  (-1  if  the command succeeded, 0 if the
                    command failed).

     \item[Command line   ]
		    The current line of the  command  string  that  is
                    being typed into TECO.

     \item[Command string scope editing]
                    The feature of TECO that is enabled  when  editing
                    is  performed  on  a  CRT terminal.  In this mode,
                    typing  the  immediate  action  {\tt <DELETE>}   command
                    causes  the  character  deleted  from  the command
                    string to physically disappear  from  the  screen.
                    Other  commands,  such  as  {\tt <CTRL/U>}  also  behave
                    differently,  taking   best   advantage   of   the
                    properties of a video terminal.

     \item[Command string]
                    The string of  TECO  commands  that  is  currently
                    being  typed  into  TECO,  or  is  currently being
                    executed by TECO.

     \item[Comment        ]
		    An informative message used within a TECO program,
                    to  make  the  code  more  readable.   The comment
                    explains the meaning and purpose of the associated
                    TECO   commands.    The  comment  is  enclosed  in
                    exclamation marks.

     \item[Compile-class command]
                    A set  of  operating  systems  commands  (such  as
                    {\tt COMPILE})  that causes compilation (translation) of
                    a source file written in a computer language  into
                    machine  instructions.   The {\tt EG}\escape command 
			is useful
                    to finish an editing session  and  re-execute  the
                    last  compile-class  command  (normally  a command
                    that compiles the file that was just edited).

     \item[Conditional    ]
		    A TECO language construct used to specify code  to
                    be   conditionally  executed  depending  upon  the
                    results of some test.  The most  general  form  of
                    the TECO conditional is
\begin{verbatim}
		n"X <then-clause> | <else-clause> '
\end{verbatim}
                    which tests the number n using  condition  X  (See
                    section \ref{Branching Commands} for details).  The commands specified
                    by the {\tt <then-clause>} are executed if the condition
                    succeeds,  otherwise the commands specified by the
                    {\tt <else-clause>} are executed.

     \item[Control-character]
                    An ASCII character whose  octal  code  is  in  the
                    range  0-37.   Usually  denoted  in this manual by
                    {\tt <CTRL/X>} where {\tt X} is the character whose 
			ASCII code
                    is 100 (octal) greater than the ASCII code for the
                    control   character   being   represented.    TECO
                    displays  such  a character as \caret {\tt X} (Caret-X) 
			except
                    for {\tt <TAB>}, {\tt <LF>}, {\tt <VT>}, {\tt <FF>}, 
		and {\tt <CR>}  which  have
                    their normal display, and {\tt <ESC>} which is displayed
                    as \$ (dollar sign) or, if a user-designated ESCAPE
                    surrogate  is  in  effect,  as  \escape  (accent grave).
                    Anytime a single control-character, {\tt <CTRL/X>} is  a
                    valid  TECO  command,  the two-character sequence,
                    \caret {\tt X}, may be used instead.

     \item[{\tt <CTRL/C>} trapping]
                    A mode of operation  wherein  a  TECO  macro  will
                    regain control (rather than TECO) when {\tt <CTRL/C>} or
                    {\tt <CTRL/C><CTRL/C>} is typed on the  user's  terminal
                    to  abort execution of the current command string.
                    {\tt <CTRL/C>}  trapping  is  enabled  by  setting   the
                    high-order bit of the ET flag.

     \item[Current character]
                    The character immediately  following  the  current
                    text buffer pointer position.

     \item[Cursor]
                    A visible  pattern  on  a  CRT  terminal  (usually
                    blinking)  that  would  specify  to  a  true scope
                    editor (like VTEDIT) the current location  of  the
                    text  buffer  pointer,  or which would specify the
                    location where subsequently typed characters would
                    be displayed.

     \item[{\tt <DELIM>}]
	            Terminology in this manual for an ESCape typed  at
                    the   console   and  passed  to  TECO.   On  newer
                    terminals, there  may  be  no  \fbox{ESCAPE}  key.   Some
                    versions   of   TECO   provide   for   an  ``ESCape
                    surrogate'', a  user-designated  key  which  is  to
                    cause transmission of an ESCape to TECO.  The term
                    {\tt <DELIM>} is used to indicate an ESCape  transmitted
                    to TECO whether it was generated by the designated
                    ``surrogate'' key or by a  ``real''  \fbox{ESCAPE}  
			key.   An
                    ESCape  types out as \escape when a surrogate is active,
                    but as {\tt \$} when no surrogate is active.

     \item[Destructive search]
                    A form of global search in  which  pages  of  text
                    that are passed over (because they did not contain
                    the  string  being  searched  for)  are  discarded
                    rather   than   written   to   the   output  file.
                    Destructive searches are initiated in TECO via use
                    of the {\tt \_} command.

     \item[Display editor]
                    A true display editor is on which  makes  efficent
                    use  of  a CRT terminal or display scope.  Such an
                    editor maintains a {\em window} into  the  text  being
                    edited.   As characters are typed on the terminal,
                    these characters immediately are entered into  the
                    text  buffer and the window is immediately updated
                    to reflect this change.  With  the  help  of  some
                    macro  support,  TECO  can  be  made  to be a true
                    display editor.   A  more  modest  use  of  a  CRT
                    terminal  (and which requires no macro support) is
                    scrolling, q.v.

     \item[Dot            ]
		    A mnemonic for {\em the current  text  buffer  pointer
                    position}.   Stems from the fact that the .  (dot,
                    or period) TECO command returns this number as its
                    value.

     \item[{\tt E} command      ]
		    One of several two-character  TECO  commands  that
                    start with the letter {\tt E}.

     \item[Echo mode      ]
		    A normal mode of  operation  in  which  TECO  will
                    automatically  echo  (display) each character that
                    is typed in response to a \caret {\tt T} command.  
		Opposite of
                    no-echo  mode.  This mode is controlled by the 8's
                    bit of the ET flag.  (0 means no-echo mode.)

     \item[ED flag        ]
		    The edit level flag.

     \item[Edit-class command]
                    A type of operating system command (such  as  MAKE
                    and  TECO)  that specifies that file editing is to
                    occur.   Many  operating  systems   remember   the
                    argument   specified   with  the  last  Edit-class
                    command, so  that  the  next  time  an  edit-class
                    command  is used without an argument, the previous
                    argument can be recalled.

     \item[Edit level flag]
                    A bit-encoded flag, referenced by the {\tt ED}  command,
                    that   describes   how  TECO  should  behave  with
                    reference to certain features.  See  section  \ref{Mode Control Flags}
                    for more details.

     \item[Edit verify flag]
                    A flag that describes how TECO  should  act  after
                    processing  of a command string.  This flag can be
                    set so that TECO will display the line just edited
                    on  the  terminal after each command.  See section
                    \ref{Mode Control Flags} for more details.

     \item[EH flag        ]
		    The help level flag.

     \item[Either-case search mode]
                    A standard mode of operation in  which  alphabetic
                    characters  specified  within  a search string are
                    permitted to match a  corresponding  character  of
                    either upper or lower case.

     \item[Else-clause    ]
		    The part of a conditional command that is executed
                    if the condition is not satisfied.  In TECO, these
                    are the commands that occur between the | and  the
                    ' characters within the conditional construct.

     \item[End-of-file flag]
                    A read-only flag, referenced  by  the  \caret {\tt N}  
			command
                    that specifies whether or not end-of-file has been
                    seen on the currently selected  input  stream.   A
                    value  of  0  means  that end-of-file has not been
                    seen;  a value of -1 means  that  end-of-file  has
                    been  reached.   This  flag  is initially 0 and is
                    reset to 0 each time a new file  is  selected  for
                    input.

     \item[EO level       ]
		    The current version level of TECO-10.

     \item[ES flag        ]
		    The search verification flag.

     \item[{\tt <ESCAPE>}       ]
		    The character whose ASCII code is 33 (octal).   It
                    is  a  general-purpose  delimiter  used  by  TECO.
                    Traditionally known  as  an  {\tt <ALTMODE>}.   When  no
                    ESCape surrogate is active, an ESCape types out as
                    \$ (dollar sign).  See also {\tt <DELIM>}.

     \item[ESCape surrogate]
                    A character (designated via the 8192  ET  bit,  or
                    via  the  EE  flag)  which  causes an ESCape to be
                    transmitted to TECO.  When an ESCape surrogate  is
                    active,  an  ESCape types out as \escape (accent grave).
                    See also {\tt <DELIM>}.

     \item[ET flag        ]
		    The terminal characteristics flag

     \item[EU flag        ]
		    The upper/lower case flag.

     \item[EV flag        ]
		    The edit verify flag.

     \item[Exact-case search mode]
                    A mode of operation in which alphabetic characters
                    within  a  search string must match the exact case
                    (upper  case  or   lower   case)   of   characters
                    specified.

     \item[Exit Protection]
                    A protective feature of TECO that prevents a  user
                    from  exiting  TECO  if a potential los of data is
                    imminent.  The {\tt EX}  and  {\tt EG}  commands  
	`		are  aborted
                    (with  the {\tt ?NFO} error message) if there is text in
                    the text buffer, but no output file is open.

     \item[F command      ]
		    One of several two-character  TECO  commands  that
                    start with the letter 'F'.

     \item[Flag           ]
		    A data register used by TECO  to  control  various
                    modes  of operation.  The contents of the flag are
                    set by specifying the new value  before  the  flag
                    name;   and the contents are returned by using the
                    flag name without a numeric  argument.   The  TECO
                    flags  are:   \caret X,  \caret E, \caret N, ED, EE, EH, EO, ES, ET,
                    EU, and EV.

     \item[Flow command   ]
		    A TECO-11 command that is used to flow (branch) to
                    a  particular  flow  control  character.  The flow
                    commands are {\tt F<}, {\tt F>}, {\tt F'}, and {\tt F|}.

     \item[Form feed flag]
                    A read-only flag, referenced  by  the  \caret {\tt E}  
			command
                    that  specifies  whether  the previous append from
                    the input file terminated because of  encountering
                    a  form  feed  character  in  the  input  file, or
                    because the text buffer became nearly  full.   The
                    value  of  this flag is automatically set to -1 by
                    TECO if input is terminated by the presence  of  a
                    form feed character in the input file.

     \item[Garbage collection]
                    A process used by TECO-10 to collect unused memory
                    when more memory is required.

     \item[Global Q-register]
                    A Q-register available throughout all macro levels
                    (including ``outside'', or at prompt level).  Global
                    Q-registers are named A-Z and 0-9.  See also \ref{Local
                    Q-Registers}, and section \ref{Q-registers}.

     \item[Global search  ]
		    A type of search that continues through the entire
                    input  file  until  the  specified  characters are
                    found.  Successive pages of the file are read into
                    the  text  buffer  and  then  written out into the
                    output  file  (if  the  string  is  not  located).
                    Global  searches  in  TECO are initiated via the {\tt N}                    
			command.

     \item[Hard-copy editing mode]
                    A mode of operation that TECO uses when the user's
                    terminal  is  not  a  CRT.   In  this mode, when a
                    character is rubbed out using  the  {\tt <DELETE>}  key,
                    the   rubbed-out  character  is  re-typed  on  the
                    terminal  as  a  visible  indication   that   this
                    character  was  rubbed  out.   Opposite  of  scope
                    editing mode.  This mode can be entered, even on a
                    scope  terminal, by turning off the 2's bit of the
                    ET flag.

     \item[Help level flag]
                    A bit-encoded flag, referenced by the {\tt EH}  command,
                    that controls properties of TECO having to do with
                    error messages and user assistance.

     \item[Immediate command]
                    A special command to  TECO  that  takes  immediate
                    effect,   requiring   no  {\tt <DELIM>}s  to  begin  its
                    execution.

                    {\em Immediate action editing characters} are commands
                    such  as  {\tt<DELETE>}  and  {\tt<CTRL/U>},  which  perform
                    editing of the TECO command string currently being
                    typed in.  See section \ref{Immediate Action Editing Characters}.

                    An   {\em immediate   inspection   command}    is    a
                    single-character command which can be typed as the
                    very  first  character  after   TECO's   prompting
                    asterisk,  and  which  causes the current location
                    counter to be  moved  by  one  line  and  the  new
                    current  line  to be typed out.  Examples are {\tt <LF>}
                    and {\tt <BS>}.  See section 
			\ref{Immediate Inspection Commands}.

                    {\em Immediate action  commands}  are  other  commands]
                    which  may  be  typed right after TECO's prompting
                    asterisk,   such   as   the   *q   to   save   the
                    previously-typed command in a Q-register or the \caret W
                    to re-display  a  scrolling  buffer  window.   See
                    section \ref{Immediate Action Commands}.

                    {\em Immediate ESCape sequence} commands  are  invoked
                    by  keys  which generate escape sequences, such as
                    arrow or ``auxiliary keypad'' keys.   See  section
                    \ref{Immediate ESCAPE-Sequence Commands}.   Such  commands  are usually used to perform
                    editing of the TECO command string currently being
                    entered  into  TECO.   For  example,  the commands
                    {\tt<DELETE>}  and  {\tt<CTRL/U>}   are   immediate   action
                    commands.

     \item[Iteration      ]
		    A language construct that permits  a  sequence  of
                    operations  to  be  re-executed  indefinitely or a
                    given  number  of  times.   In   TECO,   this   is
                    accomplished  by  enclosing  the commands in angle
                    brackets.

     \item[Kernel         ]
		    The TECO-11 kernel refers to  the  TECO-11  module
                    that implements all those features of TECO-11 that
                    are  common  to  all  PDP-11  operating   systems.
                    Operating   system   specific   features  and  the
                    interface to the operating system is  accomplished
                    by  linking an I/O module tailored for the desired
                    operating system with the kernel.

     \item[Keypad editor  ]
		    A true scope editor that uses special keys on  the
                    terminal  (such  as  a  VT52  or VT100) to control
                    editing functions.  VTEDIT  is  an  example  of  a
                    keypad editor.

     \item[Line           ]
		    A portion of text delimited by {\tt <LF>},  {\tt <VT>},  
			{\tt <FF>},
                    or  the  beginning or end of the text buffer.  The
                    final delimiter is considered to be  part  of  the
                    line.

     \item[Line-numbered file]
                    In TOPS-10,  an  ASCII  file  that  contains  line
                    numbers  embedded in the start of each line.  TECO
                    does not  require  these  line  numbers,  but  can
                    handle them if they are present.  They can also be
                    generated  or  suppressed  via  the  {\tt /GENLSN}
			   and
                    {\tt /SUPLSN} switches respectively.

     \item[Line-oriented editor]
                    An editor that  primarily  uses  line  numbers  to
                    direct  editing,  and  most  of whose commands are
                    line-oriented.   TECO  is   a   character-oriented
                    editor,  but  also  has  many facilities that work
                    with lines.

     \item[Line-wrap mode]
                    A standard mode of TECO's window  support  wherein
                    lines  that  are  too  long  to  fit  on  a single
                    physical  line  of   the   user's   terminal   are
                    automatically   continued   on   the   next  line.
                    Opposite of truncate mode.

     \item[Literal type out mode]
                    A mode that TECO can be put into  by  setting  the
                    1's bit in the ET flag, or (for a single character
                    on a one-shot basis) by using the :\caret {\tt T} 
			command.  In
                    this  mode, any characters typed by a TECO program
                    via use of one of the commands {\tt T}, {\tt V},  
			\caret {\tt A},  or  {\tt :G},
                    will  be  displayed on the user's terminal without
                    any modification.  When not  in  this  mode,  TECO
                    will convert characters that normally do not print
                    to a form that can  be  displayed  on  the  user's
                    terminal   (e.g.   {\tt <CTRL/X>}  displays  as  
			\caret {\tt X}  and
                    {\tt <ESCAPE>} displays as \$ or,  if  a  user-designated
                    ESCAPE  surrogate  is  in  effect, as \escape).  Literal
                    type  out  mode  is  useful  when  trying  to   do
                    real-time  displays  on  a  CRT  terminal.  Normal
                    (up-arrow) mode is particularly useful to let  you
                    see what characters are really in your file.

     \item[Local Q-register]
                    A Q-register available  to  only  a  single  macro
                    level  (including  ``outside'', or at prompt level).
                    The local Q-registers for a particular macro level
                    are  automatically  saved  and  restored  by  TECO
                    around execution of a  lower-level  macro.   Local
                    Q-registers  are  named .A-.Z and .0-.9.  See also
                    \ref{Global Q-Registers}, and section \ref{Q-registers}.

     \item[Log file       ]
		    An audit trail that TECO-10 can keep  showing  all
                    the  commands  that  were typed to TECO and/or all
                    the type out made by TECO.   This  is  useful  for
                    reviewing  what went wrong with a ``bad'' edit.  The
                    log file is initiated with  the  {\tt EL}  command  (see
                    Appendix 
		\ref{Incompatible, Obsolete and System-Specific Commands}.

     \item[Macro          ]
		    A sequence of TECO commands intended to be  loaded
                    into a Q-register and executed as a TECO program.

     \item[Macro level    ]
		    Two commands within the same TECO macro  are  said
                    to  be  at  the  same  macro level.  When one TECO
                    macro calls another, the calling macro is said  to
                    be at the higher macro level, and the called macro
                    at the lower macro level.

     \item[Match control construct]
                    A   command,   consisting   of   certain   special
                    characters,   used   within  a  search  string  to
                    indicate to TECO that special groups of characters
                    are permitted to match at this point.

     \item[Memory expansion]
                    TECO's act of acquiring  additional  storage  from
                    the  operating system when the currently allocated
                    storage is insufficient to handle the current TECO
                    command.   Typically, TECO will attempt to acquire
                    this additional memory before it  completely  runs
                    out  of memory, so as to allow a {\em buffer zone} for
                    the user.  This allows him to complete a few  more
                    commands  even in the case where TECO is unable to
                    get more memory.   The  informative  message  {\tt [nK
                    Bytes]}  or  its  equivalent  is  printed  on  the
                    terminal informing the user that memory usage  has
                    expanded.

     \item[Mung           ]
		    A recursive acronym for {\em Mung Until No Good} an
                    act  applied  by novice TECO users to their source
                    files.

     \item[MUNG command   ]
		    An operating  system  command  used  to  invoke  a
                    pre-written  TECO  program.  The most general form
                    of this command is {\tt MUNG file,data}  where  {\tt file}
                    is  the  name of a TECO source program, and {\tt data}
                    is data to be passed to that program.

     \item[No-echo mode   ]
		    A  mode  of  operation  in  which  TECO  will  not
                    automatically  echo  (display) the character typed
                    by the user in response to the \caret {\tt T}  
			command.   This
                    mode  is  entered by setting the 8's bit of the ET
                    flag.  Opposite of echo mode.

     \item[Page           ]
		    A portion of text delimited by  form  feeds.   The
                    form  feeds  are  not considered to be part of the
                    page.  Sometimes the term {\em page} is used to  refer
                    to all the text currently in the text buffer.

     \item[Panic Mode     ]
		    A condition that  occurs  (on  small,  single-user
                    operating   systems),   when,  in  the  middle  of
                    outputting during an edit, the output device fills
                    up so that the I/O transfer cannot continue.  TECO
                    recovers  gracefully  from   this   condition   by
                    printing  the  {\tt ?FUL}  error  message  and returning
                    control to TECO without any loss of data.  At this
                    point, the user closes the current output file and
                    opens another one on  another  device  (with  more
                    room)  and resumes editing.  At a subsequent time,
                    the two parts of his file can be concatenated back
                    together.

     \item[Pipeline editor]
                    An editor which only makes sequential edits  to  a
                    file.  The file to be edited is read into the text
                    buffer one piece at a time.  Each piece is  edited
                    and  then  written  out.   Once  a  piece has been
                    written out, further editing to that piece is  not
                    possible  unless the output file is re-opened in a
                    later edit as a new file to be edited.  TECOs  are
                    pipeline editors, with the exception of TECO-11 on
                    VAX/VMS  (which  offers  the  capability  to  page
                    backwards as well as forward).

     \item[Pointer preservation mode]
                    A mode of  operation  in  which  the  text  buffer
                    pointer  will  not  change after a failing search.
                    This mode is controlled by the 16's bit of the  ED
                    flag.

     \item[Primary input stream]
                    A term used by TECO-11 to refer to the main  input
                    file that TECO is using.

     \item[Primary output stream]
                    A term used by TECO-11 to refer to the main output
                    file that TECO is using.

     \item[Prompt level   ]
		    A TECO command is said to be executed from  prompt
                    level  if  it was typed in directly in response to
                    TECO's prompt, as opposed to being executed from a
                    macro.

     \item[Q-register     ]
		    One of  36  global  or  36  local  user-accessible
                    registers  provided  by TECO.  Each Q-register can
                    hold both a number  and  a  string  of  text.   Of
                    particular importance is the ability to store TECO
                    command strings  in  Q-registers  to  be  used  as
                    {\em macros}.

     \item[Q-register push down list]
                    A last-in first-out stack available to  users  for
                    saving and restoring the contents of Q-registers.

     \item[Read-with-no-wait mode]
                    A mode of operation in which the \caret {\tt T}  
			command  will
                    not  hang  until  a  key  is  typed  on the user's
                    terminal.  In  this  mode,  if  no  key  has  been
                    struck,  TECO  returns a -1 as the value of the \caret 
			{\tt T} command.  This mode is entered by setting the 
			32's
                    bit of the ET flag.

     \item[Scope editing mode]
                    A mode of TECO in which command line scope editing
                    (q.v.)  algorithms are used.  This mode is enabled
                    by setting the 2's bit of  the  ET  flag.   It  is
                    usually  automatically  enabled  by  TECO  if  the
                    operating system can  detect  that  the  user  has
                    invoked  TECO  from a scope terminal.  Opposite of
                    hard-copy editing mode.

     \item[Scrolling      ]
		    A  form  of  TECO  operation  available   on   CRT
                    terminals   capable   of  supporting  split-screen
                    operation.  The bottom n lines are used for TECO's
                    asterisk prompt and the usual typed command lines;
                    the  remaining  lines  above  are  used   for   an
                    automatically-updated window into the text buffer.
                    A valuable training aid:  one can experiment  with
                    TECO   commands   and  immediately  observe  their
                    effects.  Not  a  bad  idea  for  advanced  users,
                    either.  Controlled by the {\tt n,7:W} command.

     \item[SEALL mode     ]
		    A mode of window operation in which all characters
                    have  a  distinctive  visible  display,  including
                    characters such as {\tt <TAB>}, {\tt <CR>},  and  
			{\tt <LF>},  which
                    normally do not print.  Controlled by the 3:W flag
                    (see section \ref{Scope Commands}).   Also  known  as  
			{\em View  all} mode.

     \item[Search verification flag]
                    A  flag,  referenced  by  the  {\tt ES}  command,   that
                    controls  the  action  of  TECO  subsequent to the
                    execution of a command string  containg  a  search
                    command.   Proper setting of this flag will enable
                    the user to verify that  the  search  located  the
                    correct  string, by having the line containing the
                    string  found  displayed  on  the  terminal.   See
                    section \ref{Mode Control Flags} for more details.

     \item[Search mode flag]
                    A  flag,  referenced  by  the  \caret {\tt X}  
			command,   that
                    controls  how  TECO treats alphabetical characters
                    within search strings.  This flag is used  to  put
                    TECO  into  either exact-case mode, or either-case
                    mode.  If the \caret X flag is set  to  0,  then  either
                    case  matches  in searches.  If the \caret X flag is set
                    to 1, then exact case matches are required.

     \item[Secondary input stream]
                    A term used by TECO-11 to refer  to  an  auxiliary
                    input  {\em channel}  that was formed by use of the {\tt EP}
                    command.

     \item[Secondary output stream]
                    A term used by TECO-11 to refer  to  an  auxiliary
                    output  channel that was formed by use of the {\tt EA}
                    command.  See section \ref{Secondary Stream Commands} 
			for details.

     \item[Split Q-registers]
                    The feature of TECO that permits storing of both a
                    number  and  a  string  within a Q-register.  Each
                    Q-register can be considered  to  consist  of  two
                    compartments.

     \item[String build construct]
                    A command, consisting of special characters,  used
                    within a text argument to build up the contents of
                    the text argument from other components.

     \item[SUPER TECO mode]
                    A mode of TECO-8 wherein TECO will read  past  the
                    end-of-file  mark  {\tt <CTRL/Z>}  of a sequential ASCII
                    file.  This mode is enabled by using the {\tt /S} switch
                    on  an  {\tt ER} or {\tt EB} command and is terminated 
			when an
                    {\tt ER} or {\tt EB} command is  issued  with  no  
			{\tt /S}  switch.
                    This  mode  is  useful  for  scanning through mass
                    storage devices in an attempt to recover data from
                    files that had previously been deleted.

     \item[Switch]       A construct of the  form  {\tt /SWITCH}  used  
			within  a
                    command  that takes a filespecification, to modify
                    the action of the command  or  attributes  of  the
                    file specified.  Also known as a qualifier.

     \item[Tag            ]
		    A label specified within exclamation marks to mark
                    a  point  within  a  TECO program.  Control can be
                    transferred to this point by the  use  of  a  GOTO
                    ({\tt Otag}\escape) command.

     \item[TECO           ]
		    Text Editor and COrrector program.

     \item[TECO.INI       ]
		    A file containing TECO commands that is used as  a
                    user's  private  initialization  file.   When TECO
                    starts up, it looks for such a file in the  user's
                    area,  and  if  it finds one, the TECO commands in
                    this file are executed before editing commences.

     \item[TECO.TEC       ]
		    A TECO macro used by  many  operating  systems  to
                    parse the user's edit-class commands.

     \item[TECO I/O mode  ]
		    A mode of  I/O  operation  under  the  RSTS/E  and
                    RSX-11  operating  systems,  in  which  the system
                    buffers most characters and returns control to the
                    caller   (usually   TECO)  only  when  interesting
                    characters (such as {\tt<DELETE>}, {\tt <DELIM>},  
			etc.)  are
                    typed.

     \item[TECO's prompt  ]
		    refers to the asterisk ({\tt *})  that  TECO  prints  to
                    indicate that it is ready to accept commands.

     \item[TECO SIG       ]
		    A DECUS  Special  Interest  Group,  consisting  of
                    users   who   are  dedicated  to  the  spread  of,
                    improvement of, and standardization of TECO.

     \item[Terminal characteristics flag]
                    A bit-encoded flag, referenced via the ET command,
                    that contains information about the user's console
                    terminal and specifies in what manner TECO  should
                    support it.

     \item[Text buffer]
                    The main buffer used by TECO to hold the  text  to
                    be edited.

     \item[Text buffer pointer]
                    A pointer that marks the position within the  text
                    buffer where TECO currently is.  This pointer
                    always points to positions between characters;  it
                    never   points   at   a  character.   The  current
                    character  is  considred  to  be   the   character
                    immediately  to  the right of the current position
                    of the text buffer pointer.

     \item[Then-clause    ]
		    The set of commands within a conditional that  are
                    executed  if the condition is satisfied.  In TECO,
                    these commands immediately follow the  {\tt "X}  at  the
                    start  of the conditional.  They are terminated by
                    a {\tt |} or {\tt '} character.

     \item[Tracing        ]
		    The  act  of   watching   the   command-by-command
                    execution of a TECO program.  This is accomplished
                    by putting TECO into trace mode, via use of the  ?
                    command.

     \item[Trace mode     ]
		    A mode  of  TECO  wherein  each  command  that  is
                    executed  by  TECO is also displayed on the user's
                    terminal as it is being executed.   This  mode  is
                    useful  for  debugging  complicated TECO programs.
                    TECO is toggled in and out of this mode via use of
                    the  ?   command.   See  section  \ref{Tracing}  for more
                    details.

     \item[Truncate mode  ]
		    A mode of TECO's window support wherein lines that
                    are  too  long to fit on a single physical line of
                    the user's terminal are truncated when  the  right
                    margin  of the scope is encountered.  This mode is
                    entered by setting the 256's bit in the  ET  flag.
                    Opposite of line-wrap mode.

     \item[Type-out-time command]
                    A special command that makes sense only while TECO
                    is   typing  out  text  on  the  terminal.   These
                    commands are {\tt <CTRL/S>}, {\tt <CTRL/Q>}, and 
			{\tt <CTRL/O>}  and
                    affect the type out.

     \item[Up-arrow mode  ]
		    A standard mode of  operation  wherein  upon  type
                    out,  TECO  will  display  control  characters  by
                    typing the visible two-character  sequence  \caret {\tt X}
			  to
                    represent the control character {\tt <CTRL/X>}.  On many
                    older terminals, the caret  character  (\caret ),  whose
                    octal  ASCII  code  is 136, prints as an up-arrow.
                    Some  control  characters  are  not   printed   in
                    up-arrow  mode,  notably  {\tt <TAB>}, {\tt <LF>}, 
			{\tt <VT>}, {\tt <FF>}, and {\tt <CR>}.

     \item[Upper/lower case flag]
                    A  flag,  referenced  by  the  {\tt EU}  command,   that
                    specifies  whether  or  not  case  flagging  is to
                    occur.  If set to -1, no case flagging occurs.  If
                    set  to  0,  lower  case characters are flagged on
                    type out.  If set to +1, upper case characters are
                    flagged on type out.

     \item[View all mode  ]
		    A mode of window operation in which all characters
                    have  a  distinctive  visible  display,  including
                    characters such as {\tt <TAB>}, {\tt<CR>},  and  
			{\tt <LF>},  which
                    normally do not print.  Controlled by the {\tt 3:W}
			 flag
                    (see section \ref{Scope Commands}).  Also known as 
			SEALL mode.

     \item[War and Peace mode]
                    A mode of operation in which TECO outputs a  large
                    informative paragraph of information automatically
                    upon encountering an error in  a  user's  program.
                    This  paragraph of information describes the error
                    in painstaking detail and tells the  user  how  to
                    recover.  This mode is entered by setting the help
                    level to 3.  This mode is particularly  useful  to
                    Novices and particularly obnoxious to experts.

     \item[Window         ]
		    The portion of the text buffer that  is  currently
                    being   displayed   on   the  user's  terminal  or
                    auxiliary display device.

     \item[Window support]
                    Assembly language  code,  built  into  TECO,  that
                    maintains  a  window  into  the text buffer on the
                    user's terminal or auxiliary display device.

     \item[Yank protection]
                    A feature of TECO wherein any {\tt Y}, {\tt\_}, or 
			{\tt F\_}  command
                    that   will  potentially  destroy  valid  data  is
                    aborted.  This mode is normally enabled  and  will
                    cause  any of the aforementioned commands to abort
                    with the {\tt ?YCA} error message if there  is  text  in
                    the  text buffer and an output file is open.  This
                    feature can be disabled by turning off the 2's bit
                    in the ED flag.
