TECO maintains several state variables, which may be used as numeric arguments to TECO commands. When the command is executed, the current value of the designated variable becomes the numeric argument of the command.
Some of the characters which stand for specific values associated with the edit buffer have been introduced earlier in this manual. For example, the dot character (.), which represents the current pointer position, may be used in the argument of a T command. The command ".,.+5T" causes the 5 characters following the buffer pointer to be typed out. When this command is executed, the number of characters preceding the buffer pointer is substituted in each case for dot. The addition is then carried out, and the command is executed as though it were of the form m,nT.
The following lists all of the characters which have special numeric values. Any of these characters may be used as numeric argument in place of the value it represents.
| Character(s) | Function |
|---|---|
| ^B | The current date via the equation ((year - 1900)*16+month)*32+day. |
| ^E | Form feed flag. If ^E is -1, a form feed is appended when a page is output; if ^E is 0, no form feed is appended. Each time text is read into the edit buffer TECO sets the ^E flag. If the text read terminated due to a form feed (i.e., if the edit buffer was loaded with a "complete page"), ^E is set to -1. If the text read terminated because the buffer was filled to capacity before a form feed was encountered or because there was no form feed (i.e., the edit buffer was not loaded with a "complete page"), ^E is set to 0. You can set the value of the ^E flag directly, overriding the value set by the most recent buffer read. Note that any non-zero value will be treated as equivalent to -1. |
| ^H | The current time: the number of milliseconds since midnight. |
| ^N | The end of file flag. It is equal to -1 if the file open on the currently selected input stream is at end of file, and 0 otherwise. |
| ^P | The current page number. It is initialized to 1, and incremented each time a page is written with a P command. If virtual paging support is enabled, it is decremented with a -P, -Y, or -EY command is issued. If such a command pages or yanks backward before the first page, then the count will be set to 0. |
| n^Q | n^QC is identical to nL. This command returns the number of characters between the buffer pointer and the nth line separator (both positive and negative). This command converts line oriented command argument values into character-oriented argument values. Used after an expression. |
| ^R | TECO’s current radix (8, 10, or 16). |
| ^S | The negative of the length of the last insert, string found, or string inserted with a G command, whichever occurred last. To back up the pointer to the start of the last insert, string found, etc., type ^SC. |
| ^T | The ASCII code for the next input character. If the ET&4 flag bit is clear, lower case characters will be converted to upper case. If the ET&8 flag bit is set, the character will not be echoed to the terminal. If the ET&32 flag bit is set, and no character is immediately available, then -1 will be returned. Note that TECO must be built with display mode support (i.e., with the ncurses library) in order to check for the availability of an input character without waiting; otherwise, an attempt to use this feature will result in a DPY error; however, display mode does not need to be explicitly enabled. |
| ^Y | Equivalent to ".+^S,.", the m,n numeric argument spanning the text just searched for or inserted. This value may be used to recover from inserting a string in the wrong place. Type "^YXSFR`" to store the string in Q-register S and remove it from the buffer. You can then position the pointer to the right place and type "GS" to insert the string. |
| ^Z | The total number of text bytes stored in all the Q-registers (including the command line currently being executed). |
| ^^x | The combination of the Control-caret (double caret or double up-arrow) followed by any character is equivalent to the value of the ASCII code for that character. The "x" in this example may be any character that can be typed in to TECO. |
| . | Referred to as dot. The number of characters between the beginning of the edit buffer and the current position of the edit buffer pointer. |
| nA | The ASCII code for the .+n+1th character in the buffer (that is, the character to the right of buffer pointer position .+n). The expression -1A is equivalent to the ASCII code of the character immediately preceding the pointer and 0A is equivalent to the ASCII code of the character immediately following the pointer (the current character). If the character position referenced lies outside the bounds of the edit buffer, this command returns a -1. |
| B | The position preceding the first character in the buffer. Always 0. |
| F0 | Edit buffer position at start of window. Always 0 unless display mode is enabled. |
| FH | Equivalent to F0,FZ. |
| FZ | Edit buffer position at start of window. Always 0 unless display mode is enabled. |
| H | The numeric pair "B,Z", or "from the beginning of the buffer up to the end of the buffer." Thus, H represents the whole buffer. |
| n:L | Returns a count of buffer lines, according to the value of n. dot is not moved. If n = 0, returns the total number of lines in the buffer. If n < 0, returns the number of lines preceding dot. If n > 0, Returns the number of lines following dot. |
| :L | Equivalent to 0:L. |
| Mq | The Mq command (execute the contents of the text storage area of Q-register *q as a command string) may return a numeric value if the last command in the string returns a numeric value and is not followed by an ESCape. |
| The numeric value stored in Q-register q. | |
| The number of text bytes stored in Q-register q. | |
| \ | The numeric value of the digit string in the edit buffer at the current pointer position, interpreted in the current radix. The pointer is moved to the end of the digit string. |
| Z | The number of characters currently contained in the buffer. Thus, Z represents the position following the last character in the buffer. |
| \ | A backslash character which is not preceded by a numeric argument causes TECO to evaluate the digit string (if any) beginning with the character immediately following the buffer pointer and ending at the next character that is not valid for the current radix. The value becomes the numeric argument of the next command. The first character may be a digit or + or -. As the backslash command is evaluated, TECO moves the buffer pointer to a position immediately following the digit string. If there is no digit string following the pointer, the result is zero and the pointer position remains unchanged. The digits 8 and 9 will stop the evaluation if TECO’s current radix is octal. |
The following mode control flags return numeric values. The use of these flags is described here.
| Flag | Function |
|---|---|
| E1 | Current value of the extended features flag. |
| E2 | Current value of the command restrictions flag. |
| E3 | Current value of the file operations flag. |
| E4 | Current value of the display mode flag. |
| ED | Current value of the edit level flag. |
| EH | Current value of the help level flag. |
| EO | Major version number for TECO-64 (200+). |
| 0:EO | Equivalent to EO. |
| -1:EO | Minor version number for TECO-64. |
| -2:EO | Patch version number for TECO-64. |
| ES | Current value of the search verification flag. |
| ET | Current value of the type out control flag. |
| EU | Current value of the upper/lower case flag. |
| EV | Current value of the edit verify flag. |
| ^X | Current value of the search mode flag. |