man(1) Manual page archive

     TERMCAP(5)                  (5/10/80)                  TERMCAP(5)

          termcap - terminal capability data base


          Termcap is a data base describing terminals, used, e.g., by
          vi(1) and curses(3). Terminals are described in termcap by
          giving a set of capabilities which they have, and by
          describing how operations are performed.  Padding require-
          ments and initialization sequences are included in termcap.

          Entries in termcap consist of a number of `:' separated
          fields.  The first entry for each terminal gives the names
          which are known for the terminal, separated by `|' charac-
          ters.  The first name is always 2 characters long and is
          used by older version 6 systems which store the terminal
          type in a 16 bit word in a systemwide data base.  The second
          name given is the most common abbreviation for the terminal,
          and the last name given should be a long name fully identi-
          fying the terminal.  The second name should contain no
          blanks; the last name may well contain blanks for readabil-

          (P) indicates padding may be specified
          (P*) indicates that padding may be based on no. lines affected

          Name   Type  Pad?  Description
          ae     str   (P)   End alternate character set
          al     str   (P*)  Add new blank line
          am     bool        Terminal has automatic margins
          as     str   (P)   Start alternate character set
          bc     str         Backspace if not ^H
          bs     bool        Terminal can backspace with ^H
          bt     str   (P)   Back tab
          bw     bool        Backspace wraps from column 0 to last column
          CC     str         Command character in prototype if terminal settable
          cd     str   (P*)  Clear to end of display
          ce     str   (P)   Clear to end of line
          ch     str   (P)   Like cm but horizontal motion only, line stays same
          cl     str   (P*)  Clear screen
          cm     str   (P)   Cursor motion
          co     num         Number of columns in a line
          cr     str   (P*)  Carriage return, (default ^M)
          cs     str   (P)   Change scrolling region (vt100), like cm
          cv     str   (P)   Like ch but vertical only.
          da     bool        Display may be retained above
          dB     num         Number of millisec of bs delay needed

     TERMCAP(5)                  (5/10/80)                  TERMCAP(5)

          db     bool        Display may be retained below
          dC     num         Number of millisec of cr delay needed
          dc     str   (P*)  Delete character
          dF     num         Number of millisec of ff delay needed
          dl     str   (P*)  Delete line
          dm     str         Delete mode (enter)
          dN     num         Number of millisec of nl delay needed
          do     str         Down one line
          dT     num         Number of millisec of tab delay needed
          ed     str         End delete mode
          ei     str         End insert mode; give :ei=: if ic
          eo     str         Can erase overstrikes with a blank
          ff     str   (P*)  Hardcopy terminal page eject (default ^L)
          hc     bool        Hardcopy terminal
          hd     str         Half-line down (forward 1/2 linefeed)
          ho     str         Home cursor (if no cm)
          hu     str         Half-line up (reverse 1/2 linefeed)
          hz     str         Hazeltine; can't print ~'s
          ic     str   (P)   Insert character
          if     str         Name of file containing is
          im     bool        Insert mode (enter); give :im=: if ic
          in     bool        Insert mode distinguishes nulls on display
          ip     str   (P*)  Insert pad after character inserted
          is     str         Terminal initialization string
          k0-k9  str         Sent by other function keys 0-9
          kb     str         Sent by backspace key
          kd     str         Sent by terminal down arrow key
          ke     str         Out of keypad transmit mode
          kh     str         Sent by home key
          kl     str         Sent by terminal left arrow key
          kn     num         Number of other keys
          ko     str         Termcap entries for other non-function keys
          kr     str         Sent by terminal right arrow key
          ks     str         Put terminal in keypad transmit mode
          ku     str         Sent by terminal up arrow key
          l0-l9  str         Labels on other function keys
          li     num         Number of lines on screen or page
          ll     str         Last line, first column (if no cm)
          ma     str         Arrow key map, used by vi version 2 only
          mi     bool        Safe to move while in insert mode
          ml     str         Memory lock on above cursor.
          ms     bool        Safe to move while in standout and underline mode
          mu     str         Memory unlock (turn off memory lock).
          nc     bool        No correctly working carriage return (DM2500,H2000)
          nd     str         Non-destructive space (cursor right)
          nl     str   (P*)  Newline character (default \n)
          ns     bool        Terminal is a CRT but doesn't scroll.
          os     bool        Terminal overstrikes
          pc     str         Pad character (rather than null)
          pt     bool        Has hardware tabs (may need to be set with is)
          se     str         End stand out mode
          sf     str   (P)   Scroll forwards

     TERMCAP(5)                  (5/10/80)                  TERMCAP(5)

          sg     num         Number of blank chars left by so or se
          so     str         Begin stand out mode
          sr     str   (P)   Scroll reverse (backwards)
          ta     str   (P)   Tab (other than ^I or with padding)
          tc     str         Entry of similar terminal - must be last
          te     str         String to end programs that use cm
          ti     str         String to begin programs that use cm
          uc     str         Underscore one char and move past it
          ue     str         End underscore mode
          ug     num         Number of blank chars left by us or ue
          ul     bool        Terminal underlines even though it doesn't overstrike
          up     str         Upline (cursor up)
          us     str         Start underscore mode
          vb     str         Visible bell (may not move cursor)
          ve     str         Sequence to end open/visual mode
          vs     str         Sequence to start open/visual mode
          xb     bool        Beehive (f1=escape, f2=ctrl C)
          xn     bool        A newline is ignored after a wrap (Concept)
          xr     bool        Return acts like ce \r \n (Delta Data)
          xs     bool        Standout not erased by writing over it (HP 264?)
          xt     bool        Tabs are destructive, magic so char (Teleray 1061)

          A Sample Entry

          The following entry, which describes the Concept-100, is
          among the more complex entries in the termcap file as of
          this writing.  (This particular concept entry is outdated,
          and is used as an example only.)

                  :al=3*\E^R:am:bs:cd=16*\E^C:ce=16\E^S:cl=2*^L:cm=\Ea%+ %+ :co#80:\

          Entries may continue onto multiple lines by giving a \ as
          the last character of a line, and that empty fields may be
          included for readability (here between the last field on a
          line and the first field on the next).  Capabilities in
          termcap are of three types: Boolean capabilities which indi-
          cate that the terminal has some particular feature, numeric
          capabilities giving the size of the terminal or the size of
          particular delays, and string capabilities, which give a
          sequence which can be used to perform particular terminal

          Types of Capabilities

          All capabilities have two letter codes.  For instance, the
          fact that the Concept has automatic margins (i.e. an auto-
          matic return and linefeed when the end of a line is reached)
          is indicated by the capability am.  Hence the description of
          the Concept includes am.  Numeric capabilities are followed

     TERMCAP(5)                  (5/10/80)                  TERMCAP(5)

          by the character `#' and then the value.  Thus co which
          indicates the number of columns the terminal has gives the
          value `80' for the Concept.

          Finally, string valued capabilities, such as ce (clear to
          end of line sequence) are given by the two character code,
          an `=', and then a string ending at the next following `:'.
          A delay in milliseconds may appear after the `=' in such a
          capability, and padding characters are supplied by the edi-
          tor after the remainder of the string is sent to provide
          this delay.  The delay can be either a integer, e.g. `20',
          or an integer followed by an `*', i.e. `3*'.  A `*' indi-
          cates that the padding required is proportional to the num-
          ber of lines affected by the operation, and the amount given
          is the per-affected-unit padding required.  When a `*' is
          specified, it is sometimes useful to give a delay of the
          form `3.5' specify a delay per unit to tenths of millisec-

          A number of escape sequences are provided in the string val-
          ued capabilities for easy encoding of characters there.  A
          \E maps to an ESCAPE character, ^x maps to a control-x for
          any appropriate x, and the sequences \n \r \t \b \f give a
          newline, return, tab, backspace and formfeed.  Finally,
          characters may be given as three octal digits after a \, and
          the characters ^ and \ may be given as \^ and \\.  If it is
          necessary to place a : in a capability it must be escaped in
          octal as \072.  If it is necessary to place a null character
          in a string capability it must be encoded as \200.  The rou-
          tines which deal with termcap use C strings, and strip the
          high bits of the output very late so that a \200 comes out
          as a \000 would.

          Preparing Descriptions

          We now outline how to prepare descriptions of terminals.
          The most effective way to prepare a terminal description is
          by imitating the description of a similar terminal in
          termcap and to build up a description gradually, using par-
          tial descriptions with ex to check that they are correct.
          Be aware that a very unusual terminal may expose deficien-
          cies in the ability of the termcap file to describe it or
          bugs in ex. To easily test a new terminal description you
          can set the environment variable TERMCAP to a pathname of a
          file containing the description you are working on and the
          editor will look there rather than in /etc/termcap. TERMCAP
          can also be set to the termcap entry itself to avoid reading
          the file when starting up the editor.  (This only works on
          version 7 systems.)

          Basic capabilities

     TERMCAP(5)                  (5/10/80)                  TERMCAP(5)

          The number of columns on each line for the terminal is given
          by the co numeric capability.  If the terminal is a CRT,
          then the number of lines on the screen is given by the li
          capability.  If the terminal wraps around to the beginning
          of the next line when it reaches the right margin, then it
          should have the am capability.  If the terminal can clear
          its screen, then this is given by the cl string capability.
          If the terminal can backspace, then it should have the bs
          capability, unless a backspace is accomplished by a charac-
          ter other than ^H (ugh) in which case you should give this
          character as the bc string capability.  If it overstrikes
          (rather than clearing a position when a character is struck
          over) then it should have the os capability.

          A very important point here is that the local cursor motions
          encoded in termcap are undefined at the left and top edges
          of a CRT terminal.  The editor will never attempt to back-
          space around the left edge, nor will it attempt to go up
          locally off the top.  The editor assumes that feeding off
          the bottom of the screen will cause the screen to scroll up,
          and the am capability tells whether the cursor sticks at the
          right edge of the screen.  If the terminal has switch
          selectable automatic margins, the termcap file usually
          assumes that this is on, i.e. am.

          These capabilities suffice to describe hardcopy and glass-
          tty terminals.  Thus the model 33 teletype is described as


          while the Lear Siegler ADM-3 is described as

               cl|adm3|3|lsi adm3:am:bs:cl=^Z:li#24:co#80

          Cursor addressing

          Cursor addressing in the terminal is described by a cm
          string capability, with printf(3s) like escapes %x in it.
          These substitute to encodings of the current line or column
          position, while other characters are passed through
          unchanged.  If the cm string is thought of as being a func-
          tion, then its arguments are the line and then the column to
          which motion is desired, and the % encodings have the fol-
          lowing meanings:

               %d   as in printf, 0 origin
               %2   like %2d
               %3   like %3d
               %.   like %c
               %+x  adds x to value, then %.
               %>xy if value > x adds y, no output.
               %r   reverses order of line and column, no output

     TERMCAP(5)                  (5/10/80)                  TERMCAP(5)

               %i   increments line/column (for 1 origin)
               %%   gives a single %
               %n   exclusive or row and column with 0140 (DM2500)
               %B   BCD (16*(x/10)) + (x%10), no output.
               %D   Reverse coding (x-2*(x%16)), no output. (Delta Data).

          Consider the HP2645, which, to get to row 3 and column 12,
          needs to be sent \E&a12c03Y padded for 6 milliseconds.  Note
          that the order of the rows and columns is inverted here, and
          that the row and column are printed as two digits.  Thus its
          cm capability is cm=6\E&%r%2c%2Y.  The Microterm ACT-IV
          needs the current row and column sent preceded by a ^T, with
          the row and column simply encoded in binary, cm=^T%.%..
          Terminals which use %. need to be able to backspace the cur-
          sor (bs or bc), and to move the cursor up one line on the
          screen (up introduced below).  This is necessary because it
          is not always safe to transmit \t, \n ^D and \r, as the sys-
          tem may change or discard them.

          A final example is the LSI ADM-3a, which uses row and column
          offset by a blank character, thus cm=\E=%+ %+ .

          Cursor motions

          If the terminal can move the cursor one position to the
          right, leaving the character at the current position
          unchanged, then this sequence should be given as nd (non-
          destructive space).  If it can move the cursor up a line on
          the screen in the same column, this should be given as up.
          If the terminal has no cursor addressing capability, but can
          home the cursor (to very upper left corner of screen) then
          this can be given as ho; similarly a fast way of getting to
          the lower left hand corner can be given as ll; this may
          involve going up with up from the home position, but the
          editor will never do this itself (unless ll does) because it
          makes no assumption about the effect of moving up from the
          home position.

          Area clears

          If the terminal can clear from the current position to the
          end of the line, leaving the cursor where it is, this should
          be given as ce.  If the terminal can clear from the current
          position to the end of the display, then this should be
          given as cd.  The editor only uses cd from the first column
          of a line.

          Insert/delete line

          If the terminal can open a new blank line before the line
          where the cursor is, this should be given as al; this is
          done only from the first position of a line.  The cursor

     TERMCAP(5)                  (5/10/80)                  TERMCAP(5)

          must then appear on the newly blank line.  If the terminal
          can delete the line which the cursor is on, then this should
          be given as dl; this is done only from the first position on
          the line to be deleted.  If the terminal can scroll the
          screen backwards, then this can be given as sb, but just al
          suffices.  If the terminal can retain display memory above
          then the da capability should be given; if display memory
          can be retained below then db should be given.  These let
          the editor understand that deleting a line on the screen may
          bring non-blank lines up from below or that scrolling back
          with sb may bring down non-blank lines.

          Insert/delete character

          There are two basic kinds of intelligent terminals with
          respect to insert/delete character which can be described
          using termcap. The most common insert/delete character oper-
          ations affect only the characters on the current line and
          shift characters off the end of the line rigidly.  Other
          terminals, such as the Concept 100 and the Perkin Elmer Owl,
          make a distinction between typed and untyped blanks on the
          screen, shifting upon an insert or delete only to an untyped
          blank on the screen which is either eliminated, or expanded
          to two untyped blanks.  You can find out which kind of ter-
          minal you have by clearing the screen and then typing text
          separated by cursor motions.  Type abc    def using local
          cursor motions (not spaces) between the abc and the def.
          Then position the cursor before the abc and put the terminal
          in insert mode.  If typing characters causes the rest of the
          line to shift rigidly and characters to fall off the end,
          then your terminal does not distinguish between blanks and
          untyped positions.  If the abc shifts over to the def which
          then move together around the end of the current line and
          onto the next as you insert, you have the second type of
          terminal, and should give the capability in, which stands
          for insert null.  If your terminal does something different
          and unusual then you may have to modify the editor to get it
          to use the insert mode your terminal defines.  We have seen
          no terminals which have an insert mode not not falling into
          one of these two classes.

          The editor can handle both terminals which have an insert
          mode, and terminals which send a simple sequence to open a
          blank position on the current line.  Give as im the sequence
          to get into insert mode, or give it an empty value if your
          terminal uses a sequence to insert a blank position.  Give
          as ei the sequence to leave insert mode (give this, with an
          empty value also if you gave im so).  Now give as ic any
          sequence needed to be sent just before sending the character
          to be inserted.  Most terminals with a true insert mode will
          not give ic, terminals which send a sequence to open a
          screen position should give it here.  (Insert mode is

     TERMCAP(5)                  (5/10/80)                  TERMCAP(5)

          preferable to the sequence to open a position on the screen
          if your terminal has both.)  If post insert padding is
          needed, give this as a number of milliseconds in ip (a
          string option).  Any other sequence which may need to be
          sent after an insert of a single character may also be given
          in ip.

          It is occasionally necessary to move around while in insert
          mode to delete characters on the same line (e.g. if there is
          a tab after the insertion position).  If your terminal
          allows motion while in insert mode you can give the capabil-
          ity mi to speed up inserting in this case.  Omitting mi will
          affect only speed.   Some terminals (notably Datamedia's)
          must not have mi because of the way their insert mode works.

          Finally, you can specify delete mode by giving dm and ed to
          enter and exit delete mode, and dc to delete a single char-
          acter while in delete mode.

          Highlighting, underlining, and visible bells

          If your terminal has sequences to enter and exit standout
          mode these can be given as so and se respectively.  If there
          are several flavors of standout mode (such as inverse video,
          blinking, or underlining - half bright is not usually an
          acceptable standout mode unless the terminal is in inverse
          video mode constantly) the preferred mode is inverse video
          by itself.  If the code to change into or out of standout
          mode leaves one or even two blank spaces on the screen, as
          the TVI 912 and Teleray 1061 do, then ug should be given to
          tell how many spaces are left.

          Codes to begin underlining and end underlining can be given
          as us and ue respectively.  If the terminal has a code to
          underline the current character and move the cursor one
          space to the right, such as the Microterm Mime, this can be
          given as uc.  (If the underline code does not move the cur-
          sor to the right, give the code followed by a nondestructive

          Many terminals, such as the HP 2621, automatically leave
          standout mode when they move to a new line or the cursor is
          addressed.  Programs using standout mode should exit stand-
          out mode before moving the cursor or sending a newline.

          If the terminal has a way of flashing the screen to indicate
          an error quietly (a bell replacement) then this can be given
          as vb; it must not move the cursor.  If the terminal should
          be placed in a different mode during open and visual modes
          of ex, this can be given as vs and ve, sent at the start and
          end of these modes respectively.  These can be used to
          change, e.g., from a underline to a block cursor and back.

     TERMCAP(5)                  (5/10/80)                  TERMCAP(5)

          If the terminal needs to be in a special mode when running a
          program that addresses the cursor, the codes to enter and
          exit this mode can be given as ti and te.  This arises, for
          example, from terminals like the Concept with more than one
          page of memory.  If the terminal has only memory relative
          cursor addressing and not screen relative cursor addressing,
          a one screen-sized window must be fixed into the terminal
          for cursor addressing to work properly.

          If your terminal correctly generates underlined characters
          (with no special codes needed) even though it does not over-
          strike, then you should give the capability ul.  If over-
          strikes are erasable with a blank, then this should be indi-
          cated by giving eo.


          If the terminal has a keypad that transmits codes when the
          keys are pressed, this information can be given. Note that
          it is not possible to handle terminals where the keypad only
          works in local (this applies, for example, to the unshifted
          HP 2621 keys).  If the keypad can be set to transmit or not
          transmit, give these codes as ks and ke.  Otherwise the key-
          pad is assumed to always transmit.  The codes sent by the
          left arrow, right arrow, up arrow, down arrow, and home keys
          can be given as kl, kr, ku, kd, and kh respectively.  If
          there are function keys such as f0, f1, ..., f9, the codes
          they send can be given as k0, k1, ..., k9.  If these keys
          have labels other than the default f0 through f9, the labels
          can be given as l0, l1, ..., l9.  If there are other keys
          that transmit the same code as the terminal expects for the
          corresponding function, such as clear screen, the termcap 2
          letter codes can be given in the ko capability, for example,
          :ko=cl,ll,sf,sb:, which says that the terminal has clear,
          home down, scroll down, and scroll up keys that transmit the
          same thing as the cl, ll, sf, and sb entries.

          The ma entry is also used to indicate arrow keys on termi-
          nals which have single character arrow keys.  It is obsolete
          but still in use in version 2 of vi, which must be run on
          some minicomputers due to memory limitations.  This field is
          redundant with kl, kr, ku, kd, and kh.  It consists of
          groups of two characters.  In each group, the first charac-
          ter is what an arrow key sends, the second character is the
          corresponding vi command.  These commands are h for kl, j
          for kd, k for ku, l for kr, and H for kh.  For example, the
          mime would be :ma=^Kj^Zk^Xl: indicating arrow keys left
          (^H), down (^K), up (^Z), and right (^X).  (There is no home
          key on the mime.)


     TERMCAP(5)                  (5/10/80)                  TERMCAP(5)

          If the terminal requires other than a null (zero) character
          as a pad, then this can be given as pc.

          If tabs on the terminal require padding, or if the terminal
          uses a character other than ^I to tab, then this can be
          given as ta.

          Hazeltine terminals, which don't allow `~' characters to be
          printed should indicate hz.  Datamedia terminals, which echo
          carriage-return linefeed for carriage return and then ignore
          a following linefeed should indicate nc.  Early Concept ter-
          minals, which ignore a linefeed immediately after an am
          wrap, should indicate xn.  If an erase-eol is required to
          get rid of standout (instead of merely writing on top of
          it), xs should be given.  Teleray terminals, where tabs turn
          all characters moved over to blanks, should indicate xt.
          Other specific terminal problems may be corrected by adding
          more capabilities of the form xx.

          Other capabilities include is, an initialization string for
          the terminal, and if, the name of a file containing long
          initialization strings.  These strings are expected to prop-
          erly clear and then set the tabs on the terminal, if the
          terminal has settable tabs.  If both are given, is will be
          printed before if.  This is useful where if is
          /usr/lib/tabset/std but is clears the tabs first.

          Similar Terminals

          If there are two very similar terminals, one can be defined
          as being just like the other with certain exceptions.  The
          string capability tc can be given with the name of the simi-
          lar terminal.  This capability must be last and the combined
          length of the two entries must not exceed 1024. Since
          termlib routines search the entry from left to right, and
          since the tc capability is replaced by the corresponding
          entry, the capabilities given at the left override the ones
          in the similar terminal.  A capability can be cancelled with
          xx@ where xx is the capability.  For example, the entry


          defines a 2621nl that does not have the ks or ke capabili-
          ties, and hence does not turn on the function key labels
          when in visual mode.  This is useful for different modes for
          a terminal, or for different user preferences.

          /etc/termcap   file containing terminal descriptions

          ex(1), curses(3), termcap(3), tset(1), vi(1), ul(1)

     TERMCAP(5)                  (5/10/80)                  TERMCAP(5)

          William Joy
          Mark Horton added underlining and keypad support

          Ex allows only 256 characters for string capabilities, and
          the routines in termcap(3) do not check for overflow of this
          buffer.  The total length of a single entry (excluding only
          escaped newlines) may not exceed 1024.

          The ma, vs, and ve entries are specific to the vi program.

          Not all programs support all entries.  There are entries
          that are not supported by any program.