termcap -- terminal capability data base
The termcap file is a data base describing terminals, used, for example, by vi(1) and ncurses(3). Terminals are described in termcap by giving a set of capabilities that they have and by describing how operations are performed. Padding requirements 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 that are known for the ter- minal, separated by `|' characters. The first name given is the most common abbreviation for the terminal. The last name given should be a long name fully identifying the terminal, and all others are understood as synonyms for the terminal name. All names but the last should be in lower case and contain no blanks; the last name may well contain upper case characters and blanks for readability. Terminal names (except for the last, verbose entry) should be chosen using the following conventions. The particular piece of hardware making up the terminal should have a root name chosen, thus ``hp2621'' This name should not contain hyphens. Modes that the hardware can be in or user preferences should be indicated by appending a hyphen and an indicator of the mode. Therefore, a ``vt100'' in 132-column mode would be ``vt100-w''. The following suffixes should be used where possible: Suffix Meaning Example -w Wide mode (more than 80 columns) vt100-w -am With automatic margins (usually default) vt100-am -nam Without automatic margins vt100-nam -n Number of lines on screen aaa-60 -na No arrow keys (leave them in local) concept100-na -np Number of pages of memory concept100-4p -rv Reverse video concept100-rv
The description field attempts to convey the semantics of the capability. You may find some codes in the description field: (P) indicates that padding may be specified. #[1-9] in the description field indicates that the string is passed through tparm(3) or tgoto(3) with parms as given (#i). (P*) indicates that padding may vary in proportion to the number of lines affected. (#i) indicates the ith parameter. These are the boolean capabilities: Boolean TCap Description Variables Code hard_copy hc hardcopy terminal has_meta_key km Has a meta key, sets msb high has_status_line hs has extra status line insert_null_glitch in insert mode distinguishes nulls memory_above da display may be retained above the screen memory_below db display may be retained below the screen move_insert_mode mi safe to move while in insert mode move_standout_mode ms safe to move while in standout mode over_strike os terminal can overstrike status_line_esc_ok es escape can be used on the status line dest_tabs_magic_smso xt tabs destructive, magic so char (t1061) tilde_glitch hz can't print ~'s (hazeltine) transparent_underline ul underline character overstrikes xon_xoff xo terminal uses xon/xoff handshaking needs_xon_xoff nx padding won't work, xon/xoff required prtr_silent 5i printer won't echo on screen hard_cursor HC cursor is hard to see non_rev_rmcup NR enter_ca_mode does not reverse exit_ca_mode no_pad_char NP pad character does not exist non_dest_scroll_region ND scrolling region is non-destructive can_change cc terminal can re-define existing colors back_color_erase ut screen erased with background color hue_lightness_saturation hl terminal uses only HLS color notation (tektronix) col_addr_glitch YA only positive motion for column address and micro_column_address caps cr_cancels_micro_mode YB using cr turns off micro mode has_print_wheel YC printer needs operator to change character set row_addr_glitch YD only positive motion for row_address and micro_row_address caps semi_auto_right_margin YE printing in last column causes cr cpi_changes_res YF changing character pitch changes resolution lpi_changes_res YG changing line pitch changes resolution These are the numeric capabilities: Numeric TCap Description Variables Code columns co number of columns in aline init_tabs it tabs initially every # spaces lines li number of lines on screen or page lines_of_memory lm lines of memory if > line. 0 => varies magic_cookie_glitch sg number of blank chars left by enter_standout_mode or exit_standout_mode padding_baud_rate pb lowest baud rate where padding needed virtual_terminal vt virtual terminal number (CB/unix) width_status_line ws columns in status line num_labels Nl number of labels on screen label_height lh rows in each label label_width lw columns in each label max_attributes ma maximum combined attributes terminal can handle maximum_windows MW maximum number of definable windows magic_cookie_glitch_ul ug number of blanks left by underline # # These came in with SVr4's color support # # buffer_capacity Ya numbers of bytes buffered before printing dot_vert_spacing Yb spacing of pins vertically in pins per inch dot_horz_spacing Yc spacing of dots horizontally in dots per inch max_micro_address Yd maximum value in micro_..._address max_micro_jump Ye maximum value in parm_..._micro micro_char_size Yf character size when in micro mode micro_line_size Yg line size when in micro mode number_of_pins Yh numbers of pins in print-head output_res_char Yi horizontal resolution in units per line output_res_line Yj vertical resolution in units per line output_res_horz_inch Yk horizontal resolution in units per inch output_res_vert_inch Yl vertical resolution in units per inch print_rate Ym print rate in chars per second wide_char_size Yn character step size when in double wide mode buttons BT number of buttons on mouse bit_image_entwining Yo number of passed for each bit-image row bit_image_type Yp type of bit-image device These are the string capabilities: String TCap Description Variables Code back_tab bt back tab (P) bell bl audible signal (bell) (P) carriage_return cr carriage return (P*) change_scroll_region cs change region to line #1 to line #2 (P) clear_all_tabs ct clear all tab stops (P) clear_screen cl clear screen and home cursor (P*) clr_eol ce clear to end of line (P) clr_eos cd clear to end of screen (P*) column_address ch horizontal position #1, absolute (P) command_character CC terminal settable cmd character in prototype cursor_address cm move to row #1 columns #2 cursor_down do down one line cursor_home ho home cursor cursor_invisible vi make cursor invisible cursor_left le move left one space cursor_mem_address CM memory relative cursor addressing cursor_normal ve make cursor appear normal (undo cursor_invisible/cursor_visible) cursor_right nd move right one space cursor_to_ll ll last line, first column cursor_up up up one line cursor_visible vs make cursor very visible delete_character dc delete character (P*) delete_line dl delete line (P*) dis_status_line ds disable status line down_half_line hd half a line down enter_alt_charset_mode as start alternate character set (P) enter_blink_mode mb turn on blinking enter_bold_mode md turn on bold (extra bright) mode enter_ca_mode ti string to start programs using cursor_address enter_delete_mode dm enter delete mode exit_alt_charset_mode ae end alternate character set (P) exit_attribute_mode me turn off all attributes exit_ca_mode te strings to end programs using cup exit_delete_mode ed end delete mode exit_insert_mode ei exit insert mode exit_standout_mode se exit standout mode exit_underline_mode ue exit underline mode flash_screen vb visible bell (may not move cursor) form_feed ff hardcopy terminal page eject (P*) from_status_line fs return from status line init_1string i1 initialization string init_2string is initialization string init_3string i3 initialization string init_file if name of initialization file insert_character ic insert character (P) insert_line al insert line (P*) insert_padding ip insert padding after inserted character key_backspace kb backspace key key_catab ka clear-all-tabs key key_clear kC clear-screen or erase key key_ctab kt clear-tab key key_dc kD delete-character key key_dl kL delete-line key key_down kd down-arrow key key_eic kM sent by rmir or smir in insert mode key_eol kE clear-to-end-of-line key key_eos kS clear-to-end-of-screen key key_f0 k0 F0 function key key_f1 k1 F1 function key key_f10 k; F10 function key key_f2 k2 F2 function key key_f3 k3 F3 function key key_f4 k4 F4 function key key_f5 k5 F5 function key key_f6 k6 F6 function key key_f7 k7 F7 function key key_f8 k8 F8 function key key_f9 k9 F9 function key key_home kh home key key_ic kI insert-character key key_il kA insert-line key key_left kl left-arrow key key_ll kH last-line key key_npage kN next-page key key_ppage kP prev-page key key_right kr right-arrow key key_sf kF scroll-forward key key_sr kR scroll-backward key key_stab kT set-tab key key_up ku up-arrow key keypad_local ke leave 'keyboard_transmit' mode keypad_xmit ks enter 'keyboard_transmit' mode lab_f0 l0 label on function key f0 if not f0 lab_f1 l1 label on function key f1 if not f1 lab_f10 la label on function key f10 if not f10 lab_f2 l2 label on function key f2 if not f2 lab_f3 l3 label on function key f3 if not f3 lab_f4 l4 label on function key f4 if not f4 pad_char pc padding char (instead of null) parm_dch DC delete #1 chars (P*) parm_delete_line DL delete #1 lines (P*) parm_down_cursor DO down #1 lines (P*) parm_ich IC insert #1 chars (P*) parm_index SF scroll forward #1 lines (P) parm_insert_line AL insert #1 lines (P*) parm_left_cursor LE move #1 chars to the left (P) parm_right_cursor RI move #1 chars to the right (P*) parm_rindex SR scroll back #1 lines (P) parm_up_cursor UP up #1 lines (P*) pkey_key pk program function key #1 to type string #2 pkey_local pl program function key #1 to execute string #2 pkey_xmit px program function key #1 to transmit string #2 print_screen ps print contents of screen prtr_off pf turn off printer prtr_on po turn on printer repeat_char rp repeat char #1 #2 times (P*) reset_1string r1 reset string reset_2string r2 reset string reset_3string r3 reset string reset_file rf name of reset file restore_cursor rc restore cursor to last position of save_cursor row_address cv vertical position #1 absolute (P) save_cursor sc save current cursor position (P) scroll_forward sf scroll text up (P) scroll_reverse sr scroll text down (P) set_attributes sa define video attributes #1-#9 (PG9) set_tab st set a tab in every row, current columns set_window wi current window is lines #1-#2 cols #3-#4 tab ta tab to next 8-space hardware tab stop to_status_line ts move to status line underline_char uc underline char and move past it up_half_line hu half a line up init_prog iP path name of program for initialization key_a1 K1 upper left of keypad key_a3 K3 upper right of keypad key_b2 K2 center of keypad key_c1 K4 lower left of keypad key_c3 K5 lower right of keypad prtr_non pO turn on printer for #1 bytes termcap_init2 i2 secondary initialization string termcap_reset rs terminal reset string # # SVr1 capabilities stop here. IBM's version of terminfo is the same as # SVr4 up to this point, but has a different set afterwards. # char_padding rP like insert_padding but when in insert mode acs_chars ac graphics charset pairs - def=vt100 plab_norm pn program label #1 to show string #2 key_btab kB back-tab key enter_xon_mode SX turn on xon/xoff handshaking exit_xon_mode RX turn off xon/xoff handshaking enter_am_mode SA turn on automatic margins exit_am_mode RA turn off automatic margins key_command @4 command key key_copy @5 copy key key_create @6 create key key_end @7 end key key_enter @8 enter/send key key_exit @9 exit key key_find @0 find key key_help %1 help key key_mark %2 mark key key_message %3 message key key_move %4 move key key_next %5 next key key_open %6 open key key_options %7 options key key_previous %8 previous key key_print %9 print key key_redo %0 redo key key_reference &1 reference key key_refresh &2 refresh key key_replace &3 replace key key_restart &4 restart key key_resume &5 resume key key_save &6 save key key_suspend &7 suspend key key_undo &8 undo key key_sbeg &9 shifted key key_scancel &0 shifted key key_scommand *1 shifted key key_scopy *2 shifted key key_screate *3 shifted key key_sdc *4 shifted key key_sdl *5 shifted key key_select *6 select key key_send *7 shifted key key_seol *8 shifted key key_sexit *9 shifted key key_sfind *0 shifted key key_shelp #1 shifted key key_shome #2 shifted key key_sic #3 shifted key key_sleft #4 shifted key key_smessage %a shifted key key_smove %b shifted key key_snext %c shifted key key_soptions %d shifted key key_sprevious %e shifted key key_sprint %f shifted key key_sredo %g shifted key key_sreplace %h shifted key key_sright %i shifted key key_srsume %j shifted key key_ssave !1 shifted key key_ssuspend !2 shifted key key_sundo !3 shifted key req_for_input RF send next input char (for ptys) key_f11 F1 F11 function key key_f12 F2 F12 function key key_f13 F3 F13 function key key_f22 FC F22 function key key_f23 FD F23 function key key_f24 FE F24 function key key_f25 FF F25 function key key_f26 FG F26 function key key_f27 FH F27 function key key_f28 FI F28 function key key_f29 FJ F29 function key key_f30 FK F30 function key key_f31 FL F31 function key key_f32 FM F32 function key key_f33 FN F33 function key key_f34 FO F34 function key key_f35 FP F35 function key key_f36 FQ F36 function key key_f37 FR F37 function key key_f38 FS F38 function key key_f39 FT F39 function key key_f40 FU F40 function key key_f41 FV F41 function key key_f42 FW F42 function key key_f43 FX F43 function key key_f44 FY F44 function key key_f45 FZ F45 function key key_f46 Fa F46 function key key_f47 Fb F47 function key key_f48 Fc F48 function key key_f49 Fd F49 function key key_f50 Fe F50 function key key_f51 Ff F51 function key key_f52 Fg F52 function key key_f53 Fh F53 function key key_f54 Fi F54 function key key_f55 Fj F55 function key key_f56 Fk F56 function key key_f57 Fl F57 function key key_f58 Fm F58 function key key_f59 Fn F59 function key key_f60 Fo F60 function key key_f61 Fp F61 function key key_f62 Fq F62 function key key_f63 Fr F63 function key clr_bol cb Clear to beginning of line clear_margins MC clear right and left soft margins set_left_margin ML set left soft margin set_right_margin MR set right soft margin label_format Lf label format set_clock SC set clock, #1 hrs #2 mins #3 secs display_clock DK display clock at (#1,#2) remove_clock RC remove clock create_window CW define a window #1 from #2, #3 to #4, #5 goto_window WG go to window #1 hangup HU hang-up phone dial_phone DI dial number #1 quick_dial QD dial number #1 without checking tone TO select touch tone dialing pulse PU select pulse dialling flash_hook fh flash switch hook user6 u6 User string #6 user7 u7 User string #7 user8 u8 User string #8 user9 u9 User string #9 # # SVr4 added these capabilities to support color # orig_pair op Set default pair to its original value orig_colors oc Set all color pairs to the original ones initialize_color Ic initialize color #1 to (#2,#3,#4) initialize_pair Ip Initialize color pair #1 to fg=(#2,#3,#4), bg=(#5,#6,#7) set_color_pair sp Set current color pair to #1 set_foreground Sf Set foreground color #1 set_background Sb Set background color #1 # # SVr4 added these capabilities to support printers # change_char_pitch ZA Change number of characters per inch change_line_pitch ZB Change number of lines per inch change_res_horz ZC Change horizontal resolution change_res_vert ZD Change vertical resolution define_char ZE Define a character enter_doublewide_mode ZF Enter double-wide mode enter_draft_quality ZG Enter draft-quality mode enter_italics_mode ZH Enter italic mode enter_leftward_mode ZI Start leftward carriage motion enter_micro_mode ZJ Start micro-motion mode enter_near_letter_quality ZK Enter NLQ mode enter_normal_quality ZL Enter normal-quality mode enter_shadow_mode ZM Enter shadow-print mode enter_subscript_mode ZN Enter subscript mode enter_superscript_mode ZO Enter superscript mode enter_upward_mode ZP Start upward carriage motion exit_doublewide_mode ZQ End double-wide mode exit_italics_mode ZR End italic mode exit_leftward_mode ZS End left-motion mode exit_micro_mode ZT End micro-motion mode exit_shadow_mode ZU End shadow-print mode exit_subscript_mode ZV End subscript mode exit_superscript_mode ZW End superscript mode exit_upward_mode ZX End reverse character motion micro_column_address ZY Like column_address in micro mode micro_down ZZ Like cursor_down in micro mode micro_left Za Like cursor_left in micro mode micro_right Zb Like cursor_right in micro mode micro_row_address Zc Like row_address in micro mode micro_up Zd Like cursor_up in micro mode order_of_pins Ze Match software bits to print-head pins parm_down_micro Zf Like parm_down_cursor in micro mode parm_left_micro Zg Like parm_left_cursor in micro mode parm_right_micro Zh Like parm_right_cursor in micro mode parm_up_micro Zi Like parm_up_cursor in micro mode select_char_set Zj Select character set set_bottom_margin Zk Set bottom margin at current line set_bottom_margin_parm Zl Set bottom margin at line #1 or #2 lines from bottom set_left_margin_parm Zm Set left (right) margin at column #1 (#2) superscript_characters Zv List of superscriptible characters these_cause_cr Zw Printing any of these chars causes CR zero_motion Zx No motion for subsequent character # # The following string capabilities are present in the SVr4.0 term # structure, but are not documented in the man page. # char_set_names Zy List of character set names key_mouse Km Mouse event has occurred mouse_info Mi Mouse status information req_mouse_pos RQ Request mouse position get_mouse Gm Curses should get button events set_a_foreground AF Set ANSI foreground color set_a_background AB Set ANSI background color pkey_plab xl Program function key #1 to type string #2 and show string #3 device_type dv Indicate language/codeset support code_set_init ci Init sequence for multiple codesets set0_des_seq s0 Shift to code set 0 (EUC set 0, ASCII) set1_des_seq s1 Shift to code set 1 set2_des_seq s2 Shift to code set 2 set3_des_seq s3 Shift to code set 3 set_lr_margin ML Set both left and right margins to #1, #2 set_tb_margin MT Sets both top and bottom margins to #1, #2 bit_image_repeat Xy Repeat bit image cell #1 #2 times bit_image_newline Zz Move to next row of the bit image bit_image_carriage_return Yv Move to beginning of same row color_names Yw Give name for color #1 define_bit_image_region Yx Define rectangular bit image region end_bit_image_region Yy End a bit-image region set_color_band Yz Change to ribbon color #1 set_page_length YZ Set page length to #1 lines # # SVr4 added these capabilities for direct PC-clone support # display_pc_char S1 Display PC character enter_pc_charset_mode S2 Enter PC character display mode exit_pc_charset_mode S3 Exit PC character display mode enter_scancode_mode S4 Enter PC scancode mode exit_scancode_mode S5 Exit PC scancode mode pc_term_options S6 PC terminal options scancode_escape S7 Escape for scancode emulation alt_scancode_esc S8 Alternate escape for scancode emulation # # The XSI Curses standard added these. # enter_horizontal_hl_mode Xh Enter horizontal highlight mode enter_left_hl_mode Xl Enter left highlight mode enter_low_hl_mode Xo Enter low highlight mode enter_right_hl_mode Xr Enter right highlight mode enter_top_hl_mode Xt Enter top highlight mode enter_vertical_hl_mode Xv Enter vertical highlight mode Obsolete termcap capabilities. New software should not rely on them at all. Boolean TCap Description Variables Code tek_4025_insert_line xx Tektronix 4025 insert-line glitch backspaces_with_bs bs uses ^H to move left crt_no_scrolling ns crt cannot scroll no_correctly_working_cr nc no way to go to start of line Number TCap Description Variables Code backspace_delay dB padding required for ^H form_feed_delay dF padding required for ^L horizontal_tab_delay dT padding required for ^I vertical_tab_delay dV padding required for ^V number_of_function_keys kn count of function keys carriage_return_delay dC pad needed for CR new_line_delay dN pad needed for LF String TCap Description Variables Code other_non_function_keys ko list of self-mapped keycaps arrow_key_map ma map arrow keys memory_lock_above ml lock visible screen memory above the current line memory_unlock mu unlock visible screen memory above the current line linefeed_if_not_lf nl use to move down backspace_if_not_bs bc move left, if not ^H 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. ca|concept100|c100|concept|c104|concept100-4p|HDS Concept-100:\ :al=3*\E^R:am:bl=^G:cd=16*\E^C:ce=16\E^U:cl=2*^L:cm=\Ea%+ %+ :\ :co#80:.cr=9^M:db:dc=16\E^A:dl=3*\E^B:do=^J:ei=\E\200:eo:im=\E^P:in:\ :ip=16*:is=\EU\Ef\E7\E5\E8\El\ENH\EK\E\200\Eo&\200\Eo\47\E:k1=\E5:\ :k2=\E6:k3=\E7:kb=^h:kd=\E<:ke=\Ex:kh=\E?:kl=\E>:kr=\E=:ks=\EX:\ :ku=\E;:le=^H:li#24:mb=\EC:me=\EN\200:mh=\EE:mi:mk=\EH:mp=\EI:\ :mr=\ED:nd=\E=:pb#9600:rp=0.2*\Er%.%+ :se=\Ed\Ee:sf=^J:so=\EE\ED:\ :.ta=8\t:te=\Ev \200\200\200\200\200\200\Ep\r\n:\ :ti=\EU\Ev 8p\Ep\r:ue=\Eg:ul:up=\E;:us=\EG:\ :vb=\Ek\200\200\200\200\200\200\200\200\200\200\200\200\200\200\EK:\ :ve=\Ew:vs=\EW:vt#8:xn:\ :bs:cr=^M:dC#9:dT#8:nl=^J:ta=^I:pt: Entries may continue onto multiple lines by giving a \ as the last char- acter of a line, and empty fields may be included for readability (here between the last field on a line and the first field on the next). Com- ments may be included on lines beginning with ``#''. Types of Capabilities Capabilities in termcap are of three types: Boolean capabilities, which indicate particular features that the terminal has; numeric capabilities, giving the size of the display or the size of other attributes; and string capabilities, which give character sequences that can be used to perform particular terminal operations. All capabilities have two-letter codes. For instance, the fact that the Concept has automatic margins (an automatic return and linefeed when the end of a line is reached) is indi- cated by the Boolean capability am. Hence the description of the Concept includes am. `=' in such a capability, which causes padding characters to be supplied by tputs(3) after the remainder of the string is sent to provide this delay. The delay can be either a number, such as `20', or a number fol- lowed by an `*', such as `3*'. An `*' indicates that the padding required is proportional to the number of lines affected by the opera- tion, and the amount given is the per-affected-line padding required. (In the case of insert-character, the factor is still the number of lines affected; this is always 1 unless the terminal has in and the software uses it.) When an `*' is specified, it is sometimes useful to give a delay of the form `3.5' to specify a delay per line to tenths of mil- liseconds. (Only one decimal place is allowed.) A number of escape sequences are provided in the string-valued capabili- ties for easy encoding of control characters there. \E maps to an ESC character, ^X maps to a control-X for any appropriate X, and the sequences \n \r \t \b \f map to linefeed, return, tab, backspace, and formfeed, respectively. 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 as \: or be encoded as \072. If it is necessary to place a NUL character in a string capability it must be encoded as \200. (The routines that 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.) Sometimes individual capabilities must be commented out. To do this, put a period before the capability name. For example, see the first cr and ta in the example above. Preparing Descriptions 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 partial descriptions with vi(1) to check that they are correct. Be aware that a very unusual terminal may expose deficiencies in the ability of the termcap file to describe it or bugs in vi(1). To easily test a new terminal description you are working on you can put it in your home directory in a file called .termcap and programs will look there before looking in /usr/share/misc/termcap. You can also set the environment variable TERMPATH to a list of absolute file path- names (separated by spaces or colons), one of which contains the descrip- tion you are working on, and programs will search them in the order listed, and nowhere else. See termcap(3). The TERMCAP environment vari- able is usually set to the termcap entry itself to avoid reading files when starting up a program. To get the padding for insert-line right (if the terminal manufacturer did not document it), a severe test is to use vi(1) to edit /etc/passwd at 9600 baud, delete roughly 16 lines from the middle of the screen, then hit the `u' key several times quickly. If the display messes up, more padding is usually needed. A similar test can be used for insert-charac- ter. Basic Capabilities The number of columns on each line of the display is given by the co numeric capability. If the display is a CRT, then the number of lines on the screen is given by the li capability. If the display wraps around to the beginning of the next line when the cursor reaches the right margin, then it should have the am capability. If the terminal can clear its screen, the code to do this is given by the cl string capability. If the If there is a code (such as backspace) to move the cursor one position to the left, that capability should be given as le. Similarly, codes to move to the right, up, and down should be given as nd, up, and do, respectively. These local cursor motions should not alter the text they pass over; for example, you would not normally use ``nd= '' unless the terminal has the os capability, because the space would erase the charac- ter moved over. A very important point here is that the local cursor motions encoded in termcap have undefined behavior at the left and top edges of a CRT dis- play. Programs should never attempt to backspace around the left edge, unless bw is given, and never attempt to go up off the top using local cursor motions. In order to scroll text up, a program goes to the bottom left corner of the screen and sends the sf (index) string. To scroll text down, a pro- gram goes to the top left corner of the screen and sends the sr (reverse index) string. The strings sf and sr have undefined behavior when not on their respective corners of the screen. Parameterized versions of the scrolling sequences are SF and SR, which have the same semantics as sf and sr except that they take one parameter and scroll that many lines. They also have undefined behavior except at the appropriate corner of the screen. The am capability tells whether the cursor sticks at the right edge of the screen when text is output there, but this does not necessarily apply to nd from the last column. Leftward local motion is defined from the left edge only when bw is given; then an le from the left edge will move to the right edge of the previous row. This is useful for drawing a box around the edge of the screen, for example. If the terminal has switch- selectable automatic margins, the termcap description usually assumes that this feature is on, i.e., am. If the terminal has a command that moves to the first column of the next line, that command can be given as nw (newline). It is permissible for this to clear the remainder of the current line, so if the terminal has no correctly-working CR and LF it may still be possible to craft a working nw out of one or both of them. These capabilities suffice to describe hardcopy and ``glass-tty'' termi- nals. Thus the Teletype model 33 is described as T3|tty33|33|tty|Teletype model 33:\ :bl=^G:co#72:cr=^M:do=^J:hc:os: and the Lear Siegler ADM-3 is described as l3|adm3|3|LSI ADM-3:\ :am:bl=^G:cl=^Z:co#80:cr=^M:do=^J:le=^H:li#24:sf=^J: Parameterized Strings Cursor addressing and other strings requiring parameters are described by a parameterized string capability, with printf(3)-like escapes %x in it, while other characters are passed through unchanged. For example, to address the cursor the cm capability is given, using two parameters: the row and column to move to. (Rows and columns are numbered from zero and refer to the physical screen visible to the user, not to any unseen mem- ory. If the terminal has memory-relative cursor addressing, that can be indicated by an analogous CM capability.) %+x add x to value, then do %. %>xy if value > x then add y, no output %r reverse order of two parameters, no output %i increment by one, no output %n exclusive-or all parameters with 0140 (Datamedia 2500) %B BCD (16*(value/10)) + (value%10), no output %D Reverse coding (value - 2*(value%16)), no output (Delta Data). Consider the Hewlett-Packard 2645, 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 row and column coordinates is reversed here and that the row and column are sent as two-digit integers. Thus its cm capability is ``cm=6\E&%r%2c%2Y''. The Datamedia 2500 needs the current row and column sent encoded in binary using ``%.''. Terminals that use ``%.'' need to be able to backspace the cursor (le) and to move the cursor up one line on the screen (up). This is necessary because it is not always safe to transmit \n, ^D, and \r, as the system may change or discard them. (Programs using termcap must set terminal modes so that tabs are not expanded, so \t is safe to send. This turns out to be essential for the Ann Arbor 4080.) A final example is the Lear Siegler ADM-3a, which offsets row and column by a blank character, thus ``cm=\E=%+ %+ ''. Row or column absolute cursor addressing can be given as single parameter capabilities ch (horizontal position absolute) and cv (vertical position absolute). Sometimes these are shorter than the more general two-parame- ter sequence (as with the Hewlett-Packard 2645) and can be used in pref- erence to cm. If there are parameterized local motions (e.g., move n positions to the right) these can be given as DO, LE, RI, and UP with a single parameter indicating how many positions to move. These are pri- marily useful if the terminal does not have cm, such as the Tektronix 4025. Cursor Motions If the terminal has a fast way to home the cursor (to the very upper left corner of the screen), 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 a program should never do this itself (unless ll does), because it can make no assumption about the effect of moving up from the home position. Note that the home position is the same as cursor address (0,0): to the top left corner of the screen, not of memory. (Therefore, the ``\EH'' sequence on Hewlett- Packard terminals cannot be used for ho.) 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, this should be given as cd. cd must only be invoked from the first col- umn of a line. (Therefore, it can be simulated by a request to delete a large number of lines, if a true cd is not available.) Insert/Delete Line If the terminal can open a new blank line before the line containing the cursor, this should be given as al; this must be invoked only from the region. The cursor position is, alas, undefined after using this com- mand. It is possible to get the effect of insert or delete line using this command -- the sc and rc (save and restore cursor) commands are also useful. Inserting lines at the top or bottom of the screen can also be done using sr or sf on many terminals without a true insert/delete line, and is often faster even on terminals with those features. If the terminal has the ability to define a window as part of memory which all commands affect, it should be given as the parameterized string wi. The four parameters are the starting and ending lines in memory and the starting and ending columns in memory, in that order. (This terminfo(5) capability is described for completeness. It is unlikely that any termcap-using program will support it.) If the terminal can retain display memory above the screen, then the da capability should be given; if display memory can be retained below, then db should be given. These indicate that deleting a line or scrolling may bring non-blank lines up from below or that scrolling back with sr may bring down non-blank lines. Insert/Delete Character There are two basic kinds of intelligent terminals with respect to insert/delete character that can be described using termcap. The most common insert/delete character operations 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 determine the kind of terminal you have by clearing the screen 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 char- acters 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, then you have the second type of terminal and should give the capability in, which stands for ``insert null''. While these are two logically separate attributes (one line vs. multi- line insert mode, and special treatment of untyped spaces), we have seen no terminals whose insert mode cannot be described with the single attribute. The termcap entries can describe both terminals that have an insert mode and terminals that send a simple sequence to open a blank position on the current line. Give as im the sequence to get into insert mode. Give as ei the sequence to leave insert mode. Now give as ic any sequence that needs to be sent just before each character to be inserted. Most termi- nals with a true insert mode will not give ic; terminals that use a sequence to open a screen position should give it here. (If your termi- nal has both, insert mode is usually preferable to ic. Do not give both unless the terminal actually requires both to be used in combination.) If post-insert padding is needed, give this as a number of milliseconds in ip (a string option). Any other sequence that may need to be sent after insertion of a single character can also be given in ip. If your terminal needs to be placed into an `insert mode' and needs a special code preceding each inserted character, then both im/ ei and ic can be must not have mi because of the way their insert mode works. Finally, you can specify dc to delete a single character, DC with one parameter n to delete n characters, and delete mode by giving dm and ed to enter and exit delete mode (which is any mode the terminal needs to be placed in for dc to work). Highlighting, Underlining, and Visible Bells If your terminal has one or more kinds of display attributes, these can be represented in a number of different ways. You should choose one dis- play form as standout mode, representing a good high-contrast, easy-on- the-eyes format for highlighting error messages and other attention get- ters. (If you have a choice, reverse video plus half-bright is good, or reverse video alone.) The sequences to enter and exit standout mode are given as so and se, respectively. If the code to change into or out of standout mode leaves one or even two blank spaces or garbage characters on the screen, as the TVI 912 and Teleray 1061 do, then sg should be given to tell how many characters are left. Codes to begin underlining and end underlining can be given as us and ue, respectively. Underline mode change garbage is specified by ug, similar to sg. If the terminal has a code to underline the current character and move the cursor one position to the right, such as the Microterm Mime, this can be given as uc. Other capabilities to enter various highlighting modes include mb (blink- ing), md (bold or extra bright), mh (dim or half-bright), mk (blanking or invisible text), mp (protected), mr (reverse video), me (turn off all attribute modes), as (enter alternate character set mode), and ae (exit alternate character set mode). Turning on any of these modes singly may or may not turn off other modes. If there is a sequence to set arbitrary combinations of mode, this should be given as sa (set attributes), taking 9 parameters. Each parameter is either 0 or 1, as the corresponding attributes is on or off. The 9 parameters are, in order: standout, underline, reverse, blink, dim, bold, blank, protect, and alternate character set. Not all modes need be sup- ported by sa, only those for which corresponding attribute commands exist. (It is unlikely that a termcap-using program will support this capability, which is defined for compatibility with terminfo(5).) Terminals with the ``magic cookie'' glitches (sg and ug), rather than maintaining extra attribute bits for each character cell, instead deposit special ``cookies'', or ``garbage characters'', when they receive mode- setting sequences, which affect the display algorithm. Some terminals, such as the Hewlett-Packard 2621, automatically leave standout mode when they move to a new line or when the cursor is addressed. Programs using standout mode should exit standout mode on such terminals before moving the cursor or sending a newline. On termi- nals where this is not a problem, the ms capability should be present to say that this overhead is unnecessary. If the terminal has a way of flashing the screen to indicate an error quietly (a bell replacement), this can be given as vb; it must not move the cursor. If the cursor needs to be made more visible than normal when it is not on give the capability ul. If overstrikes are erasable with a blank, this should be indicated by giving eo. Keypad 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 mode (this applies, for example, to the unshifted Hewlett-Packard 2621 keys). If the keypad can be set to transmit or not transmit, give these codes as ks and ke. Otherwise the keypad 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. The codes transmitted by certain other special keys can be given: kH (home down), kb (backspace), ka (clear all tabs), kt (clear the tab stop in this column), kC (clear screen or erase), kD (delete character), kL (delete line), kM (exit insert mode), kE (clear to end of line), kS (clear to end of screen), kI (insert character or enter insert mode), kA (insert line), kN (next page), kP (previous page), kF (scroll forward/down), kR (scroll back- ward/up), and kT (set a tab stop in this column). In addition, if the keypad has a 3 by 3 array of keys including the four arrow keys, then the other five keys can be given as K1, K2, K3, K4, and K5. These keys are useful when the effects of a 3 by 3 directional pad are needed. The obsolete ko capability formerly used to describe ``other'' function keys has been completely supplanted by the above capabilities. The ma entry is also used to indicate arrow keys on terminals that 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 limita- tions. This field is redundant with kl, kr, ku, kd, and kh. It consists of groups of two characters. In each group, the first character is what an arrow key sends, and the second character is the corresponding vi com- mand. These commands are h for kl, j for kd, k for ku, l for kr, and H for kh. For example, the Mime would have ``ma=^Hh^Kj^Zk^Xl'' indicating arrow keys left (^H), down (^K), up (^Z), and right (^X). (There is no home key on the Mime.) Tabs and Initialization If the terminal needs to be in a special mode when running a program that uses these capabilities, 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 mem- ory-relative cursor addressing and not screen-relative cursor addressing, a screen-sized window must be fixed into the display for cursor address- ing to work properly. This is also used for the Tektronix 4025, where ti sets the command character to be the one used by termcap. 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 set the terminal into modes consistent with the rest of the termcap description. They are normally sent to the terminal by the tset(1) program each time the user logs in. They will be printed in the following order: is; setting tabs using ct and st; and finally if. (Terminfo uses i1-i2 instead of is and runs the program iP and prints i3 after the other initializations.) A pair of sequences that does a harder reset from a totally unknown state can be analogously given as rs and if. If the terminal has hardware tabs, the command to advance to the next tab stop can be given as ta (usually ^I). A ``backtab'' command which moves leftward to the previous tab stop can be given as bt. By convention, if the terminal driver modes indicate that tab stops are being expanded by the computer rather than being sent to the terminal, programs should not use ta or bt even if they are present, since the user may not have the tab stops properly set. If the terminal has hardware tabs that are ini- tially set every n positions when the terminal is powered up, then the numeric parameter it is given, showing the number of positions between tab stops. This is normally used by the tset(1) command to determine whether to set the driver mode for hardware tab expansion, and whether to set the tab stops. If the terminal has tab stops that can be saved in nonvolatile memory, the termcap description can assume that they are properly set. If there are commands to set and clear tab stops, they can be given as ct (clear all tab stops) and st (set a tab stop in the current column of every row). If a more complex sequence is needed to set the tabs than can be described by this, the sequence can be placed in is or if. Delays Certain capabilities control padding in the terminal driver. These are primarily needed by hardcopy terminals and are used by the tset(1) pro- gram to set terminal driver modes appropriately. Delays embedded in the capabilities cr, sf, le, ff, and ta will cause the appropriate delay bits to be set in the terminal driver. If pb (padding baud rate) is given, these values can be ignored at baud rates below the value of pb. For 4.2BSD tset(1), the delays are given as numeric capabilities dC, dN, dB, dF, and dT instead. Miscellaneous If the terminal requires other than a NUL (zero) character as a pad, this can be given as pc. Only the first character of the pc string is used. If the terminal has commands to save and restore the position of the cur- sor, give them as sc and rc. If the terminal has an extra ``status line'' that is not normally used by software, this fact can be indicated. If the status line is viewed as an extra line below the bottom line, then the capability hs should be given. Special strings to go to a position in the status line and to return from the status line can be given as ts and fs. (fs must leave the cursor position in the same place that it was before ts. If necessary, the sc and rc strings can be included in ts and fs to get this effect.) The capability ts takes one parameter, which is the column number of the sta- tus line to which the cursor is to be moved. If escape sequences and other special commands such as tab work while in the status line, the flag es can be given. A string that turns off the status line (or other- wise erases its contents) should be given as ds. The status line is nor- mally assumed to be the same width as the rest of the screen, i.e., co. If the status line is a different width (possibly because the terminal does not allow an entire line to be loaded), then its width in columns can be indicated with the numeric parameter ws. If the terminal can move up or down half a line, this can be indicated with hu (half-line up) and hd (half-line down). This is primarily useful for superscripts and subscripts on hardcopy terminals. If a hardcopy terminal can eject to the next page (form feed), give this as ff (usually If the terminal has a settable command character, such as the Tektronix 4025, this can be indicated with CC. A prototype command character is chosen which is used in all capabilities. This character is given in the CC capability to identify it. The following convention is supported on some UNIX systems: The environment is to be searched for a CC variable, and if found, all occurrences of the prototype character are replaced by the character in the environment variable. This use of the CC environ- ment variable is a very bad idea, as it conflicts with make(1). Terminal descriptions that do not represent a specific kind of known ter- minal, such as switch, dialup, patch, and network, should include the gn (generic) capability so that programs can complain that they do not know how to talk to the terminal. (This capability does not apply to virtual terminal descriptions for which the escape sequences are known.) If the terminal uses xoff/xon (DC3/DC1) handshaking for flow control, give xo. Padding information should still be included so that routines can make better decisions about costs, but actual pad characters will not be transmitted. If the terminal has a ``meta key'' which acts as a shift key, setting the 8th bit of any character transmitted, then this fact can be indicated with km. Otherwise, software will assume that the 8th bit is parity and it will usually be cleared. If strings exist to turn this ``meta mode'' on and off, they can be given as mm and mo. If the terminal has more lines of memory than will fit on the screen at once, the number of lines of memory can be indicated with lm. An explicit value of 0 indicates that the number of lines is not fixed, but that there is still more memory than fits on the screen. If the terminal is one of those supported by the UNIX system virtual ter- minal protocol, the terminal number can be given as vt. Media copy strings which control an auxiliary printer connected to the terminal can be given as ps: print the contents of the screen; pf: turn off the printer; and po: turn on the printer. When the printer is on, all text sent to the terminal will be sent to the printer. It is unde- fined whether the text is also displayed on the terminal screen when the printer is on. A variation pO takes one parameter and leaves the printer on for as many characters as the value of the parameter, then turns the printer off. The parameter should not exceed 255. All text, including pf, is transparently passed to the printer while pO is in effect. Strings to program function keys can be given as pk, pl, and px. Each of these strings takes two parameters: the function key number to program (from 0 to 9) and the string to program it with. Function key numbers out of this range may program undefined keys in a terminal-dependent man- ner. The differences among the capabilities are that pk causes pressing the given key to be the same as the user typing the given string; pl causes the string to be executed by the terminal in local mode; and px causes the string to be transmitted to the computer. Unfortunately, due to lack of a definition for string parameters in termcap, only terminfo(5) supports these capabilities. Glitches and Braindamage Hazeltine terminals, which do not allow `~' characters to be displayed, If ce is required to get rid of standout (instead of merely writing nor- mal text on top of it), xs should be given. Teleray terminals, where tabs turn all characters moved over to blanks, should indicate xt (destructive tabs). This glitch is also taken to mean that it is not possible to position the cursor on top of a ``magic cookie'', and that to erase standout mode it is necessary to use delete and insert line. The Beehive Superbee, which is unable to correctly transmit the ESC or ^C characters, has xb, indicating that the ``f1'' key is used for ESC and ``f2'' for ^C. (Only certain Superbees have this problem, depending on the ROM.) Other specific terminal problems may be corrected by adding more capabil- ities of the form x x. 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 similar terminal. This capability must be last, and the combined length of the entries must not exceed 1024. The capabilities given before tc override those in the terminal type invoked by tc. A capability can be canceled by placing xx@ to the left of the tc invocation, where xx is the capability. For example, the entry hn|2621-nl:ks@:ke@:tc=2621: defines a ``2621-nl'' that does not have the ks or ke capabilities, 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 prefer- ences.
/usr/share/misc/termcap File containing terminal descriptions. /usr/share/misc/termcap.db Hash database file containing terminal descriptions (see cap_mkdb(1)).
CAVEATS AND BUGS
The Note: termcap functions were replaced by terminfo(5) in AT&T System V UNIX Release 2.0. The transition will be relatively painless if capabil- ities flagged as ``obsolete'' are avoided. Lines and columns are now stored by the kernel as well as in the termcap entry. Most programs now use the kernel information primarily; the information in this file is used only if the kernel does not have any information. The vi(1) program allows only 256 characters for string capabilities, and the routines in termlib(3) do not check for overflow of this buffer. The total length of a single entry (excluding only escaped newlines) may not exceed 1024. Not all programs support all entries.
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