Document revision date: 15 July 2002

Buffer-change journaling creates a journal file for each text buffer. (EVE does not create buffer-change journal files for system buffers such as the Insert Here buffer, DCL buffer, or $RESTORE$ buffer.) As you edit a buffer, the journal file records the changes you make, such as erasing, inserting, or reformatting text. When you exit from EVE or when you delete the buffer, the journal files are deleted. If a system failure interrupts your editing session, the journal files are saved. Your last few keystrokes before the system failure may be lost.

Table 8-11 summarizes the EVE commands for buffer-change journaling and recovery.

Table 8-11 EVE Commands for Buffer-Change Journaling and Recovery

Command	Function or Effect
RECOVER BUFFER	Recovers a specified buffer by using the journal file for the buffer. You can specify the name of the buffer or file you want to recover or the name of the journal file for the buffer.
RECOVER BUFFER ALL	Recovers all your text buffers, one at a time, by using the journal files for the buffers, if there are any.
SET JOURNALING	Enables buffer-change journaling for a buffer that you specify.
SET JOURNALING ALL	Enables buffer-change journaling for all your buffers. This is the default setting.
SET NOJOURNALING	Disables buffer-change journaling for a buffer that you specify.
SET NOJOURNALING ALL	Disables buffer-change journaling for all your buffers.

Buffer-change journal files are written in a directory defined by the logical name TPU$JOURNAL. By default, this directory is SYS$SCRATCH, which is typically your top-level (login) directory. You can redefine the TPU$JOURNAL logical name to have the journal files written to a different directory. For example, the following commands create a subdirectory called [USER.JOURNAL] and then define TPU$JOURNAL as this subdirectory:

$ CREATE/DIRECTORY [USER.JOURNAL] $ DEFINE TPU$JOURNAL [USER.JOURNAL]

You can put the definition in your LOGIN.COM file.

Buffer-change journal files may be quite large (even larger than the text files you edit). Because of the potential size of buffer-change journal files and because there is a journal file for each text buffer, you may want to define TPU$JOURNAL as a directory or subdirectory on a large disk, rather than as SYS$SCRATCH.

Deriving Buffer-Change Journal Names

Buffer-change journal file names are derived from the name of the file or buffer being edited and the default file type for the operating system. To find out the name of the journal file for the current buffer, enter the SHOW command at the EVE prompt. The SHOW command displays the name of your input file, output file, your journal file, and other information about your current buffer.

Table 8-12 shows the buffer-change journal file names.

Table 8-12 Buffer-Change Journal File Names

Text Buffer Name	Buffer-Change Journal File
JABBER.TXT	JABBER_TXT.TPU$JOURNAL
GUMBO_RECIPE.RNO	GUMBO_RECIPE_RNO.TPU$JOURNAL
MAIN	MAIN.TPU$JOURNAL
LATEST NEWS	LATEST_NEWS.TPU$JOURNAL

Using Buffer-Change Journaling to Recover Edits

There are two ways to recover your edits with buffer-change journal files:

• Use the /RECOVER qualifier on the EDIT command line when you invoke EVE.
• Use RECOVER BUFFER commands within EVE.

In the following example, you are editing a file named JABBER.TXT when a system failure interrupts your editing session. You then use system recovery to recover your edits.

$ EDIT JABBER.TXT . . . *** system failure *** . . . $ EDIT JABBER.TXT/RECOVER

Using the RECOVER BUFFER Command

To use the recover buffer command, follow this procedure:

Step	Task
1	Invoke EVE and enter the following command to recover your text: Command: RECOVER BUFFER file-name.txt If the buffer-change journal file is available, EVE shows the following information and asks if you want to recover that buffer: Name of the buffer Original input file for the buffer, if any Output file for the buffer, if any Source file for recovery, if any Starting date and time of the editing session Journal file creation date and time
2	Press the Enter key to recover your buffer. If you do not want to recover your buffer, type No and press the Enter key. If you delete or rename the source file for recovery, the recovery fails. The source file is either the file initially read into the buffer (if any) or the last file written before the system failure. If the buffer you want to recover exists (usually the Main buffer), EVE first deletes that buffer and then does the recovery. If the buffer you want to recover has been modified, EVE asks you whether to delete the buffer before recovering.

How to Recover When You Are Unsure of the File Name

If you are unsure of the buffer names or journal file names, specify the asterisk (*) wildcard, as follows:

Command: RECOVER BUFFER *

EVE then displays a list of all your available journal files so you can choose the one you want. The list appears in an EVE system buffer named $CHOICES$ in a second window. For information about using the $CHOICES$ buffer, see the EVE online help topic called Choices Buffer.

How to Recover All Buffers

To recover all your text buffers---one at a time---use the RECOVER BUFFER ALL command. EVE then tries to recover each text buffer for which there is a buffer-change journal available. The effect is the same as repeating the RECOVER BUFFER command without having to specify buffer names or journal file names. For each text buffer, EVE displays information such as the buffer name, the files associated with the buffer, and the time and date the journal file was created. EVE prompts you for one of the following:

Response	Effect
Yes	Recovers the buffer and then asks you whether to recover the next buffer, if there is one. This is the default response. Press the Enter key.
No	Skips this recovery. If there is another buffer to recover, EVE asks you about the other buffer.
Quit	Cancels---does not recover the buffer and does not continue recovery operations.

Disabling Buffer-Change Journaling

You can disable buffer-change journaling for a particular buffer by using the SET NOJOURNALING command. To disable buffer-change journaling for all your buffers, use the SET NOJOURNALING ALL command.

Enabling Buffer-Change Journaling

If you disabled buffer-change journaling, you can enable journaling by using the SET JOURNALING command. The following command enables journaling for a buffer named JABBER.TXT:

Command: SET JOURNALING JABBER.TXT

If you invoked EVE without journaling and then want to enable buffer-change journaling during the editing session, use the SET JOURNALING ALL command (which is the EVE default).

You cannot enable buffer-change journaling if the buffer has been modified. In such a case, EVE displays the following message:

Command: SET JOURNALING MEMO.TXT Buffer MEMO.TXT is not safe for journaling

You should first write (save) the buffer by using the WRITE FILE or SAVE FILE command and then enable journaling.

8.17 EVE Formatting Commands

EVE provides commands that let you format your text by setting margins, tabs, and word wrap. You can center lines, take extra white space out of text, and insert page breaks.

Table 8-13 shows EVE editing keys and describes their functions.

Table 8-13 EVE Editing Keys and Their Functions

Key or Key Sequence	Function
Return or Ctrl/M	Inserts a carriage return at the current position either to start a new line of text or to terminate a command you are typing. On VT200, VT300, and VT400 series terminals, EVE also defines the Enter key as Return.
Tab or Ctrl/I	Inserts a tab character at the current position according to the tab modes and at the tab stops currently set.
Ctrl/L	Inserts a form-feed character at the current position to mark the beginning of a new page. A page break appears as a small double F (FF ) and is always on a line by itself. Same as INSERT PAGE BREAK.

Table 8-14 shows EVE text formatting commands and describes their functions.

Table 8-14 EVE Text Formatting Commands and Their Functions

Command	Function
CAPITALIZE WORD	Changes the case of a word, making the first letter uppercase and the rest of the letters lowercase. Works on a range, box, or single word.
CENTER LINE	Centers the current line between the left and right margins. The cursor moves with the line, remaining on the same character as the line moves.
CONVERT TABS	Converts tab characters to the appropriate number of spaces in a box, a range, or the entire buffer.
FILL	Reformats the current paragraph, range, or box according to the margins of the buffer, so the maximum number of words fits on a line. When you fill a select range or found range, the FILL or FILL RANGE command does not reformat a line that begins with a page break, a DIGITAL Standard Runoff (DSR) command, or DOCUMENT tag; it does reformat the other lines in the range. Filling a range does not delete blank lines. For more information about select range, see Section 8.9.
FILL PARAGRAPH	Reformats the paragraph that the cursor is in according to the margins set for the buffer. When you fill a paragraph, the FILL command does not reformat a line that begins with a page break, DSR command, or DOCUMENT tag; it does reformat the other lines in the paragraph.
FILL RANGE	Reformats the range or box according to the current margin settings. When you fill a select range or found range, the FILL or FILL RANGE command does not reformat a line that begins with a page break, DSR command, or DOCUMENT tag; it does reformat the other lines in the range. Filling a range does not delete blank lines.
INSERT PAGE BREAK	Inserts a form-feed character at the current position to mark the beginning of a new page. A page break appears as a small double F (FF ) and is always on a line by itself. By default, Ctrl/L is defined as INSERT PAGE BREAK.
LOWERCASE WORD	Changes the current word, range, or box to lowercase.
PAGINATE	Inserts a "soft" page break for a 54-line page. A soft page break appears as a form feed followed by the null character (FF NL ). When you enter the PAGINATE command, EVE moves back to the previous page break (if any) then checks ahead for page breaks within the next 54 lines. If any soft breaks are found within those 54 lines, EVE removes them. EVE then moves down 54 lines, inserts a soft break, and puts the cursor on the next line. The soft break is inserted on a line by itself. If a hard page break (form feed only) is found within the 54 lines, EVE stops on the line after the hard break, in case you want to erase the break.
SET LEFT MARGIN	Sets the left margin in the current buffer. The left margin must be greater than 0 but less than the right margin. By default, the left margin is 1 (leftmost column).
SET RIGHT MARGIN	Sets the right margin for the current buffer. The right margin must be greater than the left margin. By default, the right margin is one less than the width. The width is typically 80, so the default margin is typically 79.
SET PARAGRAPH INDENT	Specifies the number of spaces to be added to or subtracted from the first line of paragraphs you create or reformat. The default is 0 (no indent).
SET TABS AT	Sets tab stops at the columns that you specify. The column numbers must be in ascending order and separated by spaces. By default, tab stops are set every eight columns. The command does not affect the hardware tab settings of your terminal.
SET TABS EVERY	Sets tab stops at the specified interval. By default, tab stops are set every eight columns. The command does not affect the hardware tab settings of your terminal.
SET TABS INSERT	Default setting. Changes the tab mode so that EVE inserts a tab character at the current column when you press the Tab key. The cursor and text move to the next tab stop.
SET TABS MOVEMENT	Changes the tab mode so the Tab key becomes a cursor-movement key. Pressing the Tab key moves the cursor to the next tab stop but does not insert a tab character.
SET TABS SPACES	Changes the tab mode to insert an appropriate number of spaces, rather than a tab character, when the Tab key is pressed. Previously existing tab characters are not affected.
SET TABS INVISIBLE	Default setting. Makes tab characters invisible on the screen, appearing as white space.
SET TABS VISIBLE	Makes tab characters visible on the screen, appearing as a small HT (horizontal tab).
SET NOWRAP	Disables word wrapping at the right margin of the buffer. To start new lines, press the Enter key or use the FILL command.
SET WRAP	Default setting. Enables word wrapping at the right margin of the buffer. EVE starts new lines without you pressing the Enter key or using the FILL command.
UPPERCASE WORD	Changes the current word, range, or box to uppercase.

8.18 Using Buffers

Buffers are storage areas that exist only during an editing session. When you edit an existing file, EVE reads the contents of the file into a buffer. The highlighted status line contains the name of the buffer, its editing status (read-only or write), editing mode (insert or overstrike), and direction (forward or reverse).

Table 8-15 describes the EVE commands used to create, manipulate, and delete buffers.

Table 8-15 EVE Commands to Manipulate Buffers

Command	Function
BUFFER	Puts the specified buffer into the current window and moves the cursor to the last location it occupied in that buffer. If the specified buffer does not exist, creates a new buffer.
DELETE BUFFER	Deletes a buffer you specify by name.
GET FILE or OPEN	Puts the specified file into the current EVE window, creating a new buffer if necessary. If the file exists, EVE copies it into a new buffer in the current window. If the file does not exist, EVE creates a new, empty buffer, using the file name and file type for the buffer name. If there already is a buffer by that name, EVE asks for a different name to use.
GO TO	Returns the cursor to the location labeled by the MARK command. If the labeled location is found in another buffer, EVE moves the cursor to that buffer and puts it into the current window. (Section 8.18.5 explains how to use multiple buffers in an editing session.)
INCLUDE FILE	Inserts the contents of the specified file into the current buffer at the line above the cursor location. This is useful to combine files.
NEW	Creates a new buffer named Main and puts it into the current window. If the buffer Main already exists, EVE asks for a name for the new buffer.
NEXT BUFFER	Puts the next buffer (if one exists) into the current window and moves the cursor to the last position it occupied in that buffer. This command lets you move from one buffer to another without specifying a buffer name.
OPEN SELECTED	Opens a file whose name you have selected or found. This command is the same as using the GET FILE or OPEN command without having to type the file name.
REMOVE or CUT	If you are in the Buffer List buffer, same as DELETE BUFFER. Use the REMOVE command as follows to delete a buffer without typing the buffer name: enter the SHOW BUFFERS command (which puts you in the Buffer List buffer), move the cursor to the name of the buffer you want to delete, and enter the REMOVE command.
SAVE FILE	Writes the contents of the current buffer to the file associated with the buffer without ending the editing session. If you do not specify a file name with the SAVE FILE command, EVE prompts you for an output file specification. Similar to WRITE FILE.
SAVE FILE AS	Writes the contents of the current buffer to the file you specify without ending the editing session. For example, if you are editing a file named FIRST.DAT, you can save it as SECOND.TXT. This command does not change the name of the buffer. It does, however, associate the buffer with the file you name so that any subsequent SAVE FILE, WRITE FILE, or EXIT command writes the buffer to the file you named. This command requires you to supply a file specification.
SELECT or RETURN	If you are in the Buffer List buffer, selects the buffer you specify. Use the SELECT command as follows to select a buffer without typing the buffer name: enter the SHOW BUFFERS command, move the cursor to the name of the buffer you want to select, and enter the SELECT command.
SET BUFFER	Lets you specify the editing status of the buffer: whether the buffer can be modified or can be written to a file when you exit from EVE.
SHOW	Displays information about the buffers you have created during the editing session. If more than one buffer is active in your editing session, the SHOW command displays information about the buffer you are currently editing. For information about the other active buffers, press the Do key. To resume editing, press any other key.
SHOW BUFFERS	Lists the buffers you have created during an editing session. You can move the cursor through the list and specify a particular buffer for viewing by pressing the Select key.
SHOW DEFAULTS BUFFER	Shows information, such as margins, tab stops, direction, mode, and maximum lines, about the EVE system buffer named $DEFAULTS$. These are the default settings used when you create new buffers.
SHOW SYSTEM BUFFERS	Lists the system buffers created by EVE, such as the Message buffer, Help buffer, Insert Here buffer, and $RESTORE$ buffer. You can move the cursor through the list and specify a buffer for viewing by pressing the Select key.
WRITE FILE	Writes the contents of the current buffer to the file associated with the buffer or to the file you specify on the command line without ending the editing session. If the current buffer does not have a file specification associated with it, EVE prompts you for an output file specification. Similar to SAVE FILE.

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