NAME

se - screen editor

SYNOPSIS

se [ --acdfghiklmstuvwxyz ] [ file ... ]

DESCRIPTION

Se is a screen oriented version of ed(1). It accepts the same commands with a few differences.

Se must be run from a CRT terminal. It uses the termlib(3) terminal operations library, which retrieves terminal capabilities from the /etc/termcap database. For se to function, all of the following must be true:

1.: You must have the environment variable "TERM" set to the name of your terminal type.
2.: The /etc/termcap database must be accessible, and contain an entry for your terminal; or the "TERMCAP" environment variable must contain a description for your terminal. (See termlib(3) for details.)
3.: Your terminal must have the capability to do cursor motion.

Se first clears the screen, draws in its margins, and executes the commands in the file ./.serc, or failing that, $HOME/.serc, if either file exists. It then processes the command line, obeying the options given there, and begins reading your file (if you specified one). The .serc file is only evaluated if the euid of se matches the owner for the file and no other users have permission to write to the file. The screen it draws looks something like this. (The parenthesized numerals are not part of the screen layout, but are there to aid in the following discussion.)

	(1) (2)              (3)
	A     |
	B     |#include <stdio.h>
	C     |
	D    *|   register int i;
	E     |
	.  -> |   for (i = 1; i <= 12; i++)
	G     |      putc ('\n', stderr);
	$     |
	cmd>  |_  (4)
	11:39   myfile ........................  (5)

The display is divided into five parts: (1) the line number area, (2) the mark name area, (3) the text area, (4) the command line, and (5) the status line. The current line is indicated by the symbol "." in the line number area of the screen. In addition, a rocket ("->") is displayed to make the current line more obvious. The current mark name of each line is shown in the markname area just to the left of the vertical bar. Other information, such as the number of lines read in, the name of the file, and the time of day, are displayed in the status line.

The cursor is positioned at the beginning of the command line, showing you that se awaits your command. You may now enter any of the standard ed commands and se will perform them, while making sure that the current line is always displayed on the screen.

You can set options to control the behavior of se on the command line, simply by using a "-", followed by the option letter, and any parameters that the option may take. These options can also be set after invoking se with the options command, "o", explained in detail in the section on commands. Here is a summary:

	opt = a | c | d[dir] | f | g | h | i[a | indent] |
		k | l[lop] | lm[col] | m | s[filetype] |
	        t[tabs] | u[char] | v[col] | w[col] |
	        x | y[key] | z | -[lnr]

There are only a few other things that you need know to successfully use se:

1.: If you make an error, se automatically displays an error message in the status line. It also leaves your command line intact so that you may change it using in-line editing commands (see the "v" command). If you don't want to bother with changing the command, just hit DEL to erase the command.
2.: The "p" command has a different meaning than in ed. When used with line numbers, it displays as many of the lines in the specified range as possible (always including the last line). When used without line numbers, "p" displays the previous page.
3.: The ":" command positions a specified line at the top of the screen (e.g., "12:" positions the screen so that line 12 is at the top). If no line number is specified, ":" displays the next page.

Keeping these few differences in mind, you will see that se can perform all of the functions of ed, while giving the advantage of a "window" into the edit buffer.

Below is a summary of line number expressions, regular expressions and commands. Where there is no difference between se and ed no explanation is given.

Line Number Expressions

n: nth line.
.: current line.
$: last line.
^: previous line.
-: previous line.
capital letter A: Ath line on the screen. Se has a number of features that take advantage of the window display to minimize keystrokes and speed editing. In the line number area of the screen, se displays a capital letter for each line, but in "absolute line number" mode (controlled by the "oa" command; see the options command) se displays the actual line number of each line.
#: number of the first line on the screen.
/regular expression[/]: next line with pattern.
?regular expression[?]: previous line with pattern.
>name: number of the next line having the given markname (search wraps around, like //).
<name: number of the previous line having the given markname (search proceeds in reverse, like ??).
expression: any of the above operands may be combined with plus or minus signs to produce a line number expression. Plus signs may be omitted if desired (e.g., /parse/-5, /lexical/+2, /lexical/2, $-5, .+6, .6). Unlike ed, se does not recognize trailing "+" or "-" signs. They must always be followed by a integer. Successive "+" or "-" signs (e.g. "--") are also not allowed. However, like vi(1), se will allow you to leave off the trailing delimiter in forward searches, backward searches, in the substitute command, the join command, and in the transliteration command.

Regular Expression Notation

^: beginning of line if first character in regular expression.
.: any single character other than newline.
$: end of line if last character in regular expression.
[ccl] [^ccl]: character set.
*: 0 or more matches of the preceding regular expression element.
\: ignore special meaning of the immediately following character except "$" and "$".
$regular expression$: Tags the text actually matched by the sub-pattern specified by regular expression for use in the replacement part of a substitute command.
&: Appearing in the replacement part of a substitute command, represents the text actually matched by the pattern part of the command.
%: Appearing as the only character in the replacement part, represents the replacement part used in the previous substitute command. (This allows an empty replacement pattern as well.) If there are other characters in the replacement part along with the "%", the "%" is left alone.
\digit: Appearing in the replacement part of a substitute command, represents the text actually matched by the tagged sub-pattern specified by digit.

File names

Se will expand environment variables which appear anywhere in a path name. Identifiers in a path name are treated as environment variables if they start with a dollar sign "$". A real "$" can be used if it is escaped. If the named environment variable is not found, it is deleted from the path name. The expanded path name will be placed in the status line.

The .serc File

When se starts up, it tries to open the file .serc in your current directory. If that file cannot be found, it will attempt to open the file .serc in your home directory. If either file exists, se will read it, one line at a time, and execute each line as a command. If a line has a "#" as the first character on the line, or if the line is empty, the entire line is treated as a comment, otherwise it is executed. Here is a sample .serc file:

	# turn on tabs every 8 columns, auto indent
	ot+8
	oia

The .serc file is useful for setting up personalized options, without having to type them on the command line every time, and without using a special shell file in your bin (for sh(1)). The .serc file is only evaluated if the euid of se matches the owner for the file and no other users have permission to write to the file.

Command line options are processed after commands in the .serc file, so, in effect, command line options can be used to over-ride the defaults in your .serc file.

NOTE: Commands in the .serc file do not go through that part of se which processes the special control characters (see below), so do not use them in your .serc file.

Commands

(.)a[:text] Append

If the command is followed immediately by a colon, then whatever text follows the colon is inserted without entering "append" mode.

(.,.)c[:text] Change

If the command is followed immediately by a colon, then whatever text follows the colon is inserted in place of the named lines without entering "append" mode.

(.,.)d Delete

e["!"|"x"] [filename] Enter

"e!", enter now, is the same as "E" in ed. "ex" enters the file with "XTABS" turned on, i.e. expand any tabs to blanks. File names with extensions "s", "c", "h", "f" and "r", are automatically entered with "XTABS" turned on.

f [filename] File

(.,$)g/reg expr/command Global on pattern

none h[stuff] Help

This command provides access to on-line documentation on the screen editor. "Stuff" may be used to select which information is displayed.

(.)i[:text] Insert

If the command is immediately followed by a colon, then whatever text follows is inserted without entering "append" mode. The current line pointer is left at the last line inserted.

(^,.)j[/stuff[/]] Join

Join is basically the same in se and ed except if no line numbers are specified, the default is to join the previous line with the current line (as opposed to the current line and the next line), and se allows you to indicate what is to replace the newline(s) in "stuff". The default is a single blank. If you do specify "stuff", the trailing delimiter is optional. "j/" is considered the same as "j//", i.e., the newline is deleted.

(.,.)k[m] marK

Se allows marks to be any single character other than a newline. If "m" is not present, the lines are marked with the default name of blank. (Ed allows only lower case letters to be marks.)

none l Locate

The Locate command places the system name into the status line (e.g. "gatech" or "emory"). This is so that one can tell what machine he is using from within the screen editor. This is particularly useful for installations with many machines that can run the editor, where the user can switch back and forth between them, and become confused as to where he is at a given moment.

(.,.)mline

Move

(.,.)n[m] Name

If "m" is present, the last line in the specified range is marked with it and all other lines having that mark name are given the default mark name of blank. If "m" is not present, the names of all lines in the range are cleared.

none o[stuff] Option

Editing options may be queried or set. "Stuff" determines which options are affected. Options for se can be specified in three ways; in the .serc file, on the command line that invokes se, or with the "o" command. To specify an option with the "o" command, just enter "o" followed immediately by the option letter and its parameters. To specify an option on the command line, just use "-" followed by the option letter and its parameters. With this second method, if there are imbedded spaces in the parameter list, the entire option should be enclosed in quotes. For example, to specify the "a" (absolute line number) option and tab stops at column 8 and every fourth thereafter with the "o" command, just enter

	oa
	ot 8 +4

when se is waiting for a command. To enter the same options on the invoking command line, you might use

	se myfile -a "-t 8 +4"

You may also choose to put options that you will always want into your .serc file. Commands in the .serc file should look exactly the same as they would if they were typed at the se command line. Command line options will always over-ride option commands given in your .serc file.

The following summarizes the available se options:

a

causes absolute line numbers to be displayed in the line number area of the screen. The default behavior is to display upper-case letters with the letter "A" corresponding to the first line in the window.

c

inverts the case of all letters you type (i.e., converts upper-case to lower-case and vice versa). This option causes commands to be recognized only in upper-case and alphabetic line numbers to be displayed and recognized only in lower-case. In this mode, se displays the line number letters in lower case and expects its command letters in upper case. Unshifted letters from the terminal are converted to upper case and shifted letters to lower case.

d[dir]

selects the placement of the current line pointer following a "d" (delete) command. Dir must be either ">" or "<". If ">" is specified, the default behavior is selected: the line following the deleted lines becomes the new current line. If "<" is specified, the line immediately preceding the deleted lines becomes the new current line. If neither is specified, the current value of dir is displayed in the status line.

f

selects Fortran oriented options. This is equivalent to specifying the "ot7 +3" option, and "XTABS" is turned on (i.e. tabs are expanded).

g

controls the behavior of the "s" (substitute) command when it is under the control of a "g" (global) command. Initially, if a substitute inside a global command fails, se will not continue with the rest of the lines which might succeed. If "og" is given, then the global substitute will continue, and lines which failed will not be affected. Successive "og" commands will toggle this behavior. An explanatory message is placed in the status line.

h

controls the use of hardware line insert/delete on terminals that have that capability. By default, line insert/delete will be used if available. It is occasionally useful to turn this option off when using the editor on a terminal which can't keep up, or if the communications lines may be scrambling the control characters. Each successive "oh" merely toggles a switch within the editor. An explanatory message is placed in the status line.

i[ a | indent ]

selects indent value for lines inserted with "a", "c" and "i" commands (initially 1). "a" selects auto-indent which sets the indent to the value which equals the indent of the previous line. If neither "a" nor indent are specified, the current indent value is displayed in the status line.

k

indicates whether the current contents of your edit buffer have been saved or not by printing either a "saved" or "not saved" message on your status line.

l[lop]

sets the line number display option. Under control of this option, se continuously displays the value of one of three symbolic line numbers. lop may be ".", "#", or "$". If lop is omitted, the line number display is disabled.

lm[col]

sets the left margin to col which must be a positive integer. This option will shift your entire screen to the left, enabling you to see characters at the end of the line that were previously off the screen; the characters in columns 1 through col - 1 will not be visible. You may continue editing in the normal fashion. To reset your screen enter the command "olm 1". If col is omitted, the current left margin column is displayed in the status line.

m

controls notification of the presence of existing mail and/or the arrival of new mail in the user's mail file. The mail file is taken from the "MAIL" variable in the user's environment. On startup, if the mail file is not empty, se will remark, "You have mail." Then, if new mail arrives, se will remark, "You have new mail," and ring the terminal's bell. The "m" option simply toggles a notification switch, so that the user can turn off this notification. The "om" command displays the current setting of the notify switch in the status line.

s[d | data | as | s | c | h | n | nr | nroff | p | r | f]

sets other options for case, tabs, etc., for data files, "d" or "data", assembly files, "as" or "s", C files, "c", include files, "h", nroff files, "n" or "nr" or "nroff", ratfor files, "r", pascal files, "p", and fortran files, "f". Options set for data and nroff files are "ow74" and "ot+4"; for assembly files "ot 17+8" and "XTABS" is turned on; for C, include, pascal and ratfor files "ow74", "ot+4" and "XTABS" is turned on; for fortran files "ot 7+3" and "XTABS" is turned on. If "XTABS" is turned on then tabs are expanded. If no argument is specified the options effected by this command revert to their default value.

t[tabs]

sets tab stops according to tabs. Tabs consists of a series of numbers indicating columns in which tab stops are to be set. If a number is preceded by a plus sign ("+"), it indicates that the number is an increment; stops are set at regular intervals separated by that many columns, beginning with the most recently specified absolute column number. If no such number precedes the first increment specification, the stops are set relative to column 1. By default, tab stops are set in every third column starting with column 1, corresponding to a tabs specification of "+3". If tabs is omitted, the current tab spacing is displayed in the status line. Examples

	ot 1 4 7 10 13 16 19 22 25 28 31 34  ...
	ot +3
	ot 7 +3

Once the tab stops are set, the control-i and control-e keys can be used to move the cursor from its current position forward or backward to the nearest stop, respectively.

u[chr]

Normally, se displays a non-printing character (e.g. NEWLINE, TAB ...) as a blank. With this option, you can select the character that se displays in place of unprintable characters. Chr may be any printable character. If chr is omitted, se displays the current replacement character on the status line. Non-printing characters (such as se control characters), or any others for that matter, may be entered by hitting the ESC key followed immediately by the key to generate the desired character. Note, however, that the character you type is taken literally, exactly as it is generated by your terminal, so case conversion does not apply.

v[col]

sets the default "overlay column". This is the column at which the cursor is initially positioned by the "v" command. Col must be a positive integer, or a dollar sign ($) to indicate the end of the line. If col is omitted, the current overlay column is displayed in the status line.

w[col]

sets the "warning threshold" to col which must be a positive integer. Whenever the cursor is positioned at or beyond this column, the column number is displayed in the status line and the terminal's bell is sounded. If col is omitted, the current warning threshold is displayed in the status line. The default warning threshold is 74, corresponding to the first column beyond the right edge of the screen on an 80 column crt.

x

toggles tab compression and expansion ("XTABS"). If XTABS is off, "ox" turns it on for subsequent "r", and "w", commands. Be aware that the "e" command checks the source option for files; use the "ex" command to force tab expansion.

y[key]

allows you to edit encrypted files. "oy" followed by a key will cause the "e", "r", and "w" commands to encrypt and decrypt files using crypt(1). "oy" by itself will toggle the current encryption setting. If there is no current key, se will ask you for one. Echoing is turned off while you type your key in, and se asks you to type it in twice, just to be sure. If encryption is turned on, and you type a plain "oy", it will be turned off. Note that doing so causes se to forget the value of the encryption key. Encryption in indicated by the message "ENCRYPT" in the status line. The key is never shown on your screen.

z

suspends the editor (puts it in the background) and returns to the user's shell. (It has to be a shell that understands Berkeley job control, or else you'll be in trouble.) The editor will warn you if the edit buffer has not been saved. This is the only way to suspend the editor; the editor uses control-z for its own purposes (see the section on control characters, below). If you normally run /bin/sh without job control, this command has no effect at all.

On UNIX systems without the Berkeley job control mechanism, this option will be recognized, but will have no effect. Instead, an explanatory message will be placed in the status line.

-[lnr]

splits the screen at the line specified by lnr which must be a simple line number within the current window. All lines above lnr remain frozen on the screen, the line specified by lnr is replaced by a row of dashes, and the space below this row becomes the new window on the file. Further editing commands do not affect the lines displayed in the top part of the screen. If lnr is omitted, the screen is restored to its full size.

(.,.)p Print

Prints all the lines in the given range. As much as possible of the range is displayed, always including the last line; if no range is given, the previous page is displayed. The current line pointer is left at the last line printed.

q[!] Quit

"q!", exit immediately, is the same as "Q" in ed.

(.)r[x] [filename] Read

If no line number is specified, the named file is read starting after current line (as opposed to ed where the file is read at the end of the edit buffer). "rx" causes tabs to be expanded in the lines read.

(.,.)s[/reg expr/sub[/][g][p]] Substitute

If no pattern and replacement are specified after the "s", se will behave as if you had typed "s//%/", i.e. for the saved search pattern, substitute the saved replacement pattern. To just delete a pattern, you may type "s/stuff", and se will behave as if you had typed "s/stuff//".

(.,.)t<n> Copy

("To" is the ed mnemonic).

u[d] Undo

"u" undoes the effects of the previous command, on the last line affected (for instance a substitute command). "ud" undoes the last delete, i.e. it inserts the last deleted line after the current line. Se does not have a global undo capability.

(.,.)v oVerlay — screen oriented editing

Full screen editing with se is accomplished through the use of control characters for editing functions. With screen oriented editing, control characters may be used to modify text anywhere in the buffer. A control-v may be used to quit overlay mode. A control-f may be used to restore the current line to its original state and terminate the command. Since se supports such a large number of control functions, the mnemonic value of control character assignments has dwindled to almost zero. About the only thing mnemonic is that most symmetric functions have been assigned to opposing keys on the keyboard (e.g., forward and backward tab to control-i and control-e, forward and backward space to control-g and control-h, skip right and left to control-o and control-w, and so on). We feel pangs of conscience about this, but can find no more satisfactory alternative. If you feel the control character assignments are terrible and you can find a better way, you may change them by modifying the definitions in se and recompiling.

Except for a few special purpose ones, control characters can be used anywhere, even on the command line. (This is why erroneous commands are not erased — you may want to edit them.) Most of the functions work on a single line, but the cursor may be positioned anywhere in the buffer. Refer to the next section which describes each control character in detail.

(1,$)w[+ | > | !] [filename] Write

Write the portion of the buffer specified to the named file. If "+" or ">" is given, the portion of the buffer is appended to the file; otherwise the portion of the buffer replaces the file. "w!", write immediately, is the same as "W" in ed.

(1,$)x/reg expr/command eXclude on pattern

(.,.)y[/from/to[/][p]] TranslYterate (sic)

The range of characters specified by "from" is transliterated into the range of characters specified by "to". The last line on which something was transliterated is printed if the "p" option is used. The last line in the range becomes the new current line. As with the substitute and join commands, and pattern searches, the trailing delimiter is optional. Se saves both the "from" and "to" parts of the transliterate command: "y" is the same as "y//%/", i.e. transliterate the saved "from" range into the saved "to" range. The "%" is special only if it is the only character in the "to" part of the command.

(.,.)zbleft[,right][char]DrawBox

A box is drawn on the given lines, in the given columns, using the given char. This command can be used as an aid for preparing block diagrams, flowcharts, or tables.

Line numbers are used to specify top and bottom row positions of the box. Left and right specify left and right column positions of the box. If second line number is omitted, the box degenerates to a horizontal line. If right-hand column is omitted, the box degenerates to a vertical line. If char is omitted, it defaults to blank, allowing erasure of a previously-drawn box.

For example, "1,10zb15,25*" would draw a box 10 lines high and 11 columns across, using asterisks. The upper left corner of the box would be on line 1, column 15, and the lower right corner on line 10, column 25.

(.)= Equals what line number?

(1,$)~mcommand global exclude on markname

Similar to the "x" prefix except that "command" is performed for all lines in the range that do not have the mark name "m".

(1,$)'mcommand global on markname

Similar to the "g" prefix except that "command" is performed for all lines in the range that have the mark name "m".

(.): display next page

The next page of the buffer is displayed and the current line pointer is placed at the top of the window.

none ![UNIX command] escape to the shell

The user's choice of shell is taken from the "SHELL" environment variable (if it exists), and is used to execute UNIX command if it is present. Otherwise, an interactive shell is created. After an interactive shell exits, the screen is immediately redrawn. If a command was run, the results are left on the screen, and the user must type RETURN to redraw the editing window. This is how vi(1) behaves. If the first character of the UNIX command is a `!', then the `!' is replaced with the text of the previous shell command. An unescaped `%' in the UNIX command will be replaced with the current saved file name. If the shell command is expanded, se will echo it first, and then execute it. This behavior is identical to the version of ed in UNIX System V.

Control Characters

The set of control characters defined below can be used for correcting mistakes while typing regular editing commands, for correcting commands that have caused an error message to be displayed, for correcting lines typed in append mode, or for in-line editing using the "v" command.

control-a: Toggle insert mode. The status of the insertion indicator is inverted. Insert mode, when enabled, causes the characters you type to be inserted at the current cursor position in the line instead of overwriting the characters that were there previously. When insert mode is in effect, "INSERT" appears in the status line.
control-b: Scan right and erase. The current line is scanned from the current cursor position to the right margin until an occurrence of the next character typed is found. When the character is found, all characters from the current cursor position up to (but not including) the scanned character are deleted and the remainder of the line is moved to the left to close the gap. The cursor is left in the same column which is now occupied by the scanned character. If the line to the right of the cursor does not contain the character being sought, the terminal's bell is sounded. Se remembers the last character that was scanned using this or any of the other scanning keys; if control-b is hit twice in a row, this remembered character is used instead of a literal control-b.
control-c: Insert blank. The characters at and to the right of the current cursor position are moved to the right one column and a blank is inserted to fill the gap.
control-d: Cursor up. The effect of this key depends on se's current mode. When in command mode, the current line pointer is moved to the previous line without affecting the contents of the command line. If the current line pointer is at line 1, the last line in the file becomes the new current line. In overlay mode (viz. the "v" command), the cursor is moved up one line while remaining in the same column. In append mode, this key is ignored.
control-e: Tab left. The cursor is moved to the nearest tab stop to the left of its current position.
control-f: "Funny" return. The effect of this key depends on the editor's current mode. In command mode, the current command line is entered as-is, but is not erased upon completion of the command; in append mode, the current line is duplicated; in overlay mode (viz. the "v" command), the current line is restored to its original state and command mode is reentered (except if under control of a global prefix).
control-g: Cursor right. The cursor is moved one column to the right.
control-h: Cursor left. The cursor is moved one column to the left. Note that this does not erase any characters; it simply moves the cursor.
control-i: Tab right. The cursor is moved to the next tab stop to the right of its current position. Again, no characters are erased.
control-k: Cursor down. As with the control-d key, this key's effect depends on the current editing mode. In command mode, the current line pointer is moved to the next line without changing the contents of the command line. If the current line pointer is at the last line in the file, line 1 becomes the new current line. In overlay mode (viz. the "v" command), the cursor is moved down one line while remaining in the same column. In append mode, control-k has no effect.
control-l: Scan left. The cursor is positioned according to the character typed immediately after the control-l. In effect, the current line is scanned, starting from the current cursor position and moving left, for the first occurrence of this character. If none is found before the beginning of the line is reached, the scan resumes with the last character in the line. If the line does not contain the character being looked for, the message "NOT FOUND" is printed in the status line. Se remembers the last character that was scanned for using this key; if the control-l is hit twice in a row, this remembered character is searched for instead of a literal control-l. Apart from this, however, the character typed after control-l is taken literally, so se's case conversion feature does not apply.
control-m: Kill right and terminate; identical to the NEWLINE key described below.
control-n: Scan left and erase. The current line is scanned from the current cursor position to the left margin until an occurrence of the next character typed is found. Then that character and all characters to its right up to (but not including) the character under the cursor are erased. The remainder of the line, as well as the cursor are moved to the left to close the gap. If the line to the left of the cursor does not contain the character being sought, the terminal's bell is sounded. If control-n is hit twice in a row, the last character scanned for is used instead of a literal control-n.
control-o: Skip right. The cursor is moved to the first position beyond the current end of line.
control-p: Interrupt. If executing any command except "a", "c", "i" or "v", se aborts the command and reenters command mode. The command line is not erased. This is the only way to interrupt the editor. Se ignores the SIGQUIT signal (see signal(2)); in fact it disables generating quits from the terminal. The editor uses ASCII FS (control-\) for its own purposes, and changes the terminal driver to make control-p be the interrupt character.
control-]: Fix screen. The screen is reconstructed from se's internal representation of the screen.
control-r: Erase right. The character at the current cursor position is erased and all characters to its right are moved left one position.
control-j: Scan right. This key is identical to the control-l key described above, except that the scan proceeds to the right from the current cursor position.
control-t: Kill right. The character at the current cursor position and all those to its right are erased.
control-u: Erase left. The character to the left of the current cursor position is deleted and all characters to its right are moved to the left to fill the gap. The cursor is also moved left one column, leaving it over the same character.
control-v: Skip right and terminate. The cursor is moved to the current end of line and the line is terminated.
control-w: Skip left. The cursor is positioned at column 1.
control-x: Insert tab. The character under the cursor is moved right to the next tab stop; the gap is filled with blanks. The cursor is not moved.
control-y: Kill left. All characters to the left of the cursor are erased; those at and to the right of the cursor are moved to the left to fill the void. The cursor is left in column 1.
control-z: Toggle case conversion mode. The status of the case conversion indicator is inverted; if case inversion was on, it is turned off, and vice versa. Case inversion, when in effect, causes all upper case letters to be converted to lower case, and all lower case letters to be converted to upper case (just like the alpha-lock key on some terminals). You can type control-z at any time to toggle the case conversion mode. When case inversion is in effect, se displays the word "CASE" in the status line. Note that se continues to recognize alphabetic line numbers in upper case only, in contrast to the "case inversion" option (see the description of options under the option command).
control-_ (US): Insert newline. A newline character is inserted before the current cursor position, and the cursor is moved one position to the right. The newline is displayed according to the current non-printing replacement character (see the "u" option).
control-\ (FS): Tab left and erase. Characters are erased starting with the character at the nearest tab stop to the left of the cursor up to but not including the character under the cursor. The rest of the line, including the cursor, is moved to the left to close the gap.
Use control-p to interrupt the editor.
control-^ (control-~, RS): Tab right and erase. Characters are erased starting with the character under the cursor up to but not including the character at the nearest tab stop to the right of the cursor. The rest of the line is then shifted to the left to close the gap.
NEWLINE: Kill right and terminate. The characters at and to the right of the current cursor position are deleted, and the line is terminated.
DEL: Kill all. The entire line is erased, along with any error message that appears in the status line.
ESC: Escape. The ESC key provides a means for entering se's control characters literally as text into the file. In fact, any character that can be generated from the keyboard is taken literally when it immediately follows the ESC key. If the character is non-printing (as are all of se's control characters), it appears on the screen as the current non-printing replacement character (normally a blank — see the options command "ou").

Windowing Systems

On 4.3 BSD, and on the AT&T Unix/PC or 3B1, se notices when its current window changes size or is repositioned, and adjusts the screen image accordingly.

FILES

$HOME/.serc: se initialization file.
/usr/tmp/process id.sequence_number: for scratch file.
./se.hangup: where se dumps its buffer if it catches a hang-up signal.
/usr/local/lib/se_h/*: help scripts for the "h" command.

DIAGNOSTICS

Self explanatory diagnostics appear in the status line.

CAVEATS

Se will never dump its buffer into an encrypted file when it encounters a hang-up, even if encryption was turned on at the time.

BUGS

Can only be run from a script if the script is first passed through scriptse(1).

Tabs could be handled better. This is because se was originally written for Prime computers.

Does not check whether or not it has been put into the background (this is to allow se to be used with the USENET news software, which does a poor job of signal handling for child processes).

Occasionally flakes out the screen when doing line inserts and deletes, due to problems within the termlib(3) package in putting out the right number of padding characters. Type a control-] to redraw the screen.

The auto-indent feature does not recognize a line consisting of just blanks and then a "." to terminate input, when the "." is not in the same position as the first non-blank character of the previous line.

There is no global undo capability.

The help screens could use a rewrite.

AUTHORS

Se started out as the version of ed that came with the book "Software Tools," by Kernighan and Plauger, which was written in Ratfor. On the Pr1me computers at the School of Information and Computer Science at Georgia Tech, Dan Forsyth, Perry Flinn, and Alan Akin added all the enhancements suggested in the exercises in the book, and some more of their own. Jack Waugh made extensive modifications to turn the line editor into a screen editor; further work was done by Dan Forsyth. All of this was in an improved Georgia Tech version of Ratfor.

Later, Dan Forsyth, then at Medical Systems Development Corporation, converted the Ratfor version into C, for Berkeley Unix (4.1 BSD). At Georgia Tech, Arnold Robbins took the C version and added many new features and improvements, the most important of which was termlib support and System V support. The existing help screens were edited and completed at that time, as well. This was finished in early 1985.

In early 2013, Thomas Cort continued maintenance of se, modernizing the code base and build system to support current POSIX operating systems. Thomas' primary motivation is to preserve this bit of computing history. His goals are to squash any remaining bugs and make se as portable as possible. No major new features will be added. He can be reached at tcort@se-editor.org