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- .; $Id: m2.rno,v 1.2 1985/01/27 20:08:36 tom Exp $
- .ch BROWSE Commands
- .; more commands
- .;.req "d0.req"
- This chapter describes in detail the BROWSE browsing commands.
-
- .hl Scrolling Commands
- BROWSE permits you to scroll forward or backward in units of a half-screen,
- or left or right in units of a column.
- The restriction to half-screen scrolling is made to reduce the
- overhead required to examine a file.
- This permits you to examine files which are larger than those which
- you could edit.
- .b
- Most scrolling operations are performed in a single keystroke.
- You may provide a repeat-count to modify the basic half-screen
- operations.
-
- .hl+1 Forward/Backward
- You may scroll through your file in either direction.
- BROWSE provides you with several commands for this purpose:
- .lm+8
- .b.i-4
- .x Control characters>CTRL/U
- .x U, up
- U The UP command (also CTRL/U)
- directs BROWSE to scroll up by one half-screen.
- You may not scroll up past the beginning of the file.
- .b.i-4
- .x Control characters>CTRL/D
- .x D, down
- D The DOWN command (also CTRL/D)
- directs BROWSE to scroll down by one half-screen.
- You may not scroll past the end of the file.
- .b.i-4
- .x Control characters>CTRL/F
- .x F, forward
- F The FORWARD command (also CTRL/F and space)
- directs BROWSE to scroll down by a full screen.
- .b.i-4
- .x Control characters>CTRL/B
- .x B, backward
- B The BACKWARD command (also CTRL/B)
- directs BROWSE to scroll up by a full screen.
- .b.i-4
- .x Control characters>CTRL/T
- .x T, top
- T The TOP command (also CTRL/T)
- directs BROWSE to scroll to the top of the file (i.e., the first line).
- .b.i-4
- .x Control characters>CTRL/E
- .x E, end
- E The END command (also CTRL/E)
- directs BROWSE to scroll to the end of the file.
- .b.lm-8
- As you scroll or skip forward through a file,
- BROWSE constructs a table which permits it to rapidly return to
- the places where you have been.
- This is useful for returning to the end of the file.
- It also permits BROWSE to return to the same point on upward scrolling.
- Each half-screen display overlaps by one line.
- The overlap-lines are the tabulated positions in the file.
- .b
- .x Number>Repeat count
- By supplying a number before the scrolling command,
- you direct BROWSE to repeat that operation (without, of course
- the extra screen operations).
- For example, if you type
- .b;########10D
- .b;BROWSE will scroll forward by ten half-screens (normally 110 lines).
- (Repeat counts are not applicable to the TOP and END commands.)
- .b
- Whenever BROWSE skips forward into a part of the file it has not read
- before, it displays (in the status line) the half-screen number
- which it is currently reading.
- Because I/O on a heavily-loaded VMS system may be slow,
- this tells you how far BROWSE has gotten.
- Scrolling to parts of the file which you have previously viewed
- is much more rapid;
- BROWSE need reread only the text to display on that screen.
- .b
- .x Arrow keys>UP-ARROW
- .x Arrow keys>DOWN-ARROW
- The arrow keys (UP-ARROW and DOWN-ARROW) are normally assigned
- to the UP and DOWN half-screen scrolling commands.
-
- .hl Aborting a Scrolling Operation
- .x X, aborting I/O
- If you direct BROWSE to scroll to the end of a file,
- it will attempt to do just that.
- However, you may change your mind;
- you hadn't realized just how big the file really was.
- To stop BROWSE, type "X".
- This will cause BROWSE to cease reading new pages.
- The last screen read will be displayed.
-
- .hl Left/Right
- You may direct BROWSE to display the file shifted to the left or the right.
- Unlike vertical scrolling, you may scroll left or right by single columns.
- BROWSE provides you with several horizontal-scrolling commands:
- .lm+8
- .b.i-4
- .x Control characters>CTRL/H
- .y Control characters>Backspace, see CTRL/H
- .x H, home
- H The HOME command (also CTRL/H, or backspace) returns the
- display to the "home" column (the leftmost one).
- .b.i-4
- .x Control characters>CTRL/J
- .y Control characters>LINE-FEED, see CTRL/J
- .x J, jump to end-of-line
- J The JUMP command (also CTRL/J, or LINE-FEED) causes BROWSE
- to scroll right until the end of the longest line (in the current
- range of lines) is visible in the display.
- .b.i-4
- .x Control characters>CTRL/L
- .x L, left
- L The LEFT command (also CTRL/L) causes BROWSE to scroll left
- by one half-screen.
- You may not scroll left past the home-column.
- .b.i-4
- .x Control characters>CTRL/R
- .x R, right
- R The RIGHT command (also CTRL/R) causes BROWSE to scroll right by
- one half-screen.
- Right-scrolling is limited, based on the current display mode and
- the maximum record length of the file.
- .lm-8
- .b
- You may modify the operation of the HOME, LEFT and RIGHT commands
- by providing a number before the command:
- .lm+8
- .b.i-4
- .x Number>Columns
- o A number provided for the HOME command directs BROWSE to
- scroll left or right, placing that particular column at the leftmost
- position in the screen.
- .b.i-4
- .x Number>Repeat count
- o A number provided for the LEFT or RIGHT command directs
- BROWSE to scroll left or right by that number of columns.
- .lm-8
- .b
- .x Arrow keys>LEFT-ARROW
- .x Arrow keys>RIGHT-ARROW
- The arrow keys (LEFT-ARROW and RIGHT-ARROW) are normally assigned to
- the LEFT and RIGHT commands.
-
- .hl Column and Line Display
- There are many applications in which you need to know the exact location
- of parts of the file which you are examining.
- .x Ruler-mode
- .x Toggle-commands>"__", Ruler-mode
- BROWSE provides you with a "ruler" mode.
- When you select ruler-mode (by typing an underscore, "__")
- BROWSE changes the status line to a combined scale plus line number.
- The cursor's column is reflected in the scale;
- its line number is shown as well.
- Examples of ruler-mode display are reproduced in Figures 1-6 and 1-8.
- .b
- You may move the cursor in units of single columns or lines using
- the arrow keys.
- You may temporarily exit ruler mode, and return.
- The cursor will return to the point at which you exited ruler mode
- (unless, of course, you scroll to a new screen).
- .b
- .x Ruler-mode
- The following commands are provided in ruler mode:
- .lm+8
- .x Arrow keys>UP-ARROW
- .b.i-4;UP-ARROW
- .br;moves the cursor up one line.
- If the cursor is already at the top-of-screen,
- BROWSE scrolls up by a half-screen.
- .x Arrow keys>DOWN-ARROW
- .b.i-4;DOWN-ARROW
- .br;moves the cursor down one line.
- If the cursor is already at the bottom of the current screen,
- BROWSE scrolls down by a half-screen.
- .x Arrow keys>LEFT-ARROW
- .b.i-4;LEFT-ARROW
- .br;moves the cursor left one column.
- If the cursor is in the leftmost display-column,
- BROWSE scrolls left by a half-screen.
- .x Arrow keys>RIGHT-ARROW
- .b.i-4;RIGHT-ARROW
- .br;moves the cursor right one column.
- If the cursor is at the end of the scale,
- BROWSE scrolls to the right by a half-screen.
- .x Control characters>CTRL/H
- .x H, home
- .b.i-4;H (also CTRL/H, or backspace)
- moves the cursor to the HOME-column.
- If the cursor is already in the HOME-column,
- BROWSE moves the cursor up one line.
- .x Control characters>CTRL/I
- .y Control characters>TAB, see CTRL/I
- .x I, tab
- .b.i-4;I (also CTRL/I, or TAB)
- moves the cursor right, to the next tab stop (multiples of 8 columns).
- .x Control characters>CTRL/J
- .x J, jump to end-of-line
- .b.i-4;J (also CTRL/J, or LINE-FEED)
- moves the cursor to the end of the current display line.
- If the cursor is already at the end of the display line,
- BROWSE moves the cursor down one line.
- .b.lm-8
- You may modify the effect of the arrow keys, as well as the
- I-command by prefixing the command with a repeat count.
- .b
- .x Ruler-mode
- In ruler mode, you may use the other BROWSE commands as well.
-
- .hl-1 Searching
- .x Highlighting>Searching
- BROWSE provides you with a simple, easy to use search command.
- It displays the points in the file at which the target is found
- by highlighting each occurrence.
- .;
- .hl+1 Initiating a Search
- .x "/", search forward
- .x "_\", search backward
- To initiate a search, type "/" or "_\".
- A forward slash ("/") initiates a forward search;
- a backward slash ("_\") a backward search.
- BROWSE will prompt you for a search target.
- You may provide only printing characters (counting space).
- .x Control characters>CTRL/U
- .x Control characters>CTRL/X
- .x CTRL/U, abort input
- .x CTRL/X, abort input
- To make corrections, use the DELETE key, or CTRL/U or CTRL/X to abort the
- input.
- Hit the RETURN or ENTER key to complete the text-entry.
- .b
- Whatever you have entered becomes the current search target.
- A space in your target matches any number of white-space characters
- (i.e., space, TAB, FORM-FEED or RETURN) in the display.
- BROWSE begins searching in the current screen for matches against this target.
- If no matches are found, BROWSE continues the search in the given direction.
- If BROWSE reaches the end of the file without finding a match,
- it sounds an alarm, and retains its original position.
- If a match is found, BROWSE scrolls to the corresponding screen
- and highlights all matching positions.
- .x Highlighting>Searching
- Matching positions which happen to lie to the left or right of
- the current column limits are flagged by highlighting the end of
- the display line closest to the match.
- .b
- .x Control characters>CTRL/U
- .x Control characters>CTRL/X
- .x CTRL/U, abort input
- .x CTRL/X, abort input
- If you provide no input (i.e., by hitting CTRL/U or CTRL/X, or by simply
- hitting RETURN), this clears the search target.
- .x Highlighting>Overstruck text
- If no search target is active, BROWSE highlights overstruck text.
- .;
- .hl Continuing a Search
- You may continue a search in either direction,
- regardless of the direction in which you initiated it:
- .lm+8
- .b.i-4
- .x Control characters>CTRL/N
- .x N, next
- N The NEXT command (also CTRL/N) directs BROWSE to search forward
- in the file, for the next matching positions.
- .b.i-4
- .x Control characters>CTRL/P
- .x P, previous
- P The PREVIOUS command (also CTRL/P) directs BROWSE to search backward
- in the file, for the previous matches.
- .lm-8
- .;
- .hl Aborting a Search
- .x X, aborting I/O
- Searching a file always requires I/O, and can be slow.
- If you wish to stop a search, type "X".
- This will cause BROWSE to halt the search, and return to its original position.
-
- .hl-1 Altering the Display Format
- BROWSE is used to examine ^&text\& files, rather than ^&binary\& ones.
- You may direct BROWSE to display your file in alternate forms to see its
- structure (i.e., the actual characters used to make up overstrikes,
- and the record numbering).
- The alternatives are intentionally limited to those which are applicable
- to text (or printer) files.
- You may not, for instance, use BROWSE as a screen-oriented hexadecimal dump
- (it strips parity from all characters).
- Nor does BROWSE interpret escape sequences (it prevents them from
- affecting your screen).
- .b
- BROWSE, in fact, is designed to be quite robust.
- It can display the contents of any sequential file without
- causing your terminal to lock up.
- Any control characters which are not in its repertoire are
- converted to "_^"-form (e.g., ESCAPE becomes "_^_[").
- You may use BROWSE to examine binary (".EXE" and ".OBJ") files.
- Note, however, that a LINE-FEED always causes BROWSE to begin a
- new line.
- .;
- .hl+1 Overstrikes
- .x Highlighting>Overstruck text
- Normally BROWSE interprets overstruck text (created by either backspacing
- or embedded RETURN characters) and highlights it.
- For binary files, this may be inappropriate.
- Or you may wish to expand the sequence of characters which make up
- the overstruck text.
- .x Control characters>Noncommand>CTRL/O
- To do this, use the O-command ("O" only, not CTRL/O).
- BROWSE will alter its interpretation of backspace and RETURN characters.
- Backspaces are shown as "_^H", and RETURN as "_^M".
- Tab characters also are shown as "_^I".
- .x Toggle-commands>O, overstrikes
- .y O, see Toggle-commands
- To undo this command, type "O" again; it simply toggles the display.
- .b
- If you have invoked BROWSE with the qualifier
- .b;########/OVER:2
- .b;then the O-command becomes a three-state toggle.
- The third state shows all control characters (except LINE-FEED) as a ".".
- This permits you to examine a binary file looking only for character
- strings.
- .b
- Figure 1-3 illustrates the second state of the O-command.
- Figures 1-7 and 1-8 illustrate the third state of the O-command.
- .;
- .hl Marks and Record Numbers
- You may also use BROWSE to examine the record structure of a text file.
- VMS files are organized in records
- which may be of any length up to 32768 characters.
- Files may have either variable record lengths, or fixed (i.e., all the same).
- For most text files, records are synonymous with lines,
- i.e., the record attributes imply carriage control at the end of each
- record.
- However, there are files (such as those produced by RUNOFF) which
- do not have carriage control.
- Also, even for files having carriage control attributes,
- carriage control characters (e.g., LINE-FEED) may be embedded within
- a record.
- BROWSE makes sense of all this and shows your file as it really is.
- .b
- When it opens a file for examination, BROWSE allocates a buffer large
- enough to show the longest display line which could be made.
- Files with no carriage control attributes are assumed to be like those
- produced by RUNOFF:
- each record contains characters as needed to produce the desired
- carriage control.
- BROWSE appends records until a LINE-FEED is found, either explicitly,
- or as part of the record attributes.
- (You may override this action with the "/NOJOIN" qualifier).
- .b
- A record may correspond to a fraction of a display line,
- or it may be one or more display lines.
- You may examine the record structure of the display by using the
- "_^"- and M-commands:
- .lm+8
- .b.i-4
- .x Toggle-commands>"_^", Set temporary MARK-mode
- .y M, see Toggle-commands
- .x Toggle-commands>M, mark (file-address)
- o The "_^" command sets MARK-mode.
- BROWSE redisplays the current screen with a prefix before each
- line (see Figures 1-4, 1-5, 1-7 and 1-8).
- There are either two or four columns of numbers shown in the prefix:
- .lm+8
- .b.i-4
- - If two, the first is the record file address (the number of
- characters from the beginning of the file), and the second is the
- display line number.
- .b.i-4
- - If four, the first is the record file address,
- the second is the offset into a record, and the third and
- fourth are the record number and line number.
- .lm-8
- .b.i-4
- .x Toggle-commands>M, mark (file-address)
- .y Control characters>RETURN, see CTRL/M
- .x Control characters>CTRL/M
- o The M-command (also CTRL/M or RETURN) toggles this prefix mode,
- showing the record lengths, rather than their offsets.
- It is a three-state toggle; the third state resumes the original
- display mode.
- .b.lm-8
- Normally the M-command becomes inactive again on reaching the
- original display mode.
- .x /MARKS qualifier
- If you use the qualifier
- .b;########/MARKS
- .b;however, it is permanently enabled.
-
- .hl-1 Other Commands
- The remaining BROWSE commands are all one-of-a-kind,
- but all useful:
- .;
- .hl+1 Exiting from BROWSE
- .x Control characters>Noncommand>CTRL/Q
- .x Control characters>CTRL/Z
- .x Q, quit
- .x Z, end-of-input (quit)
- To exit from BROWSE, use the Q (quit) command, or Z (also CTRL/Z).
- .;
- .hl Help-Screen
- .x "?", help
- .x PF2, help
- You may obtain online help from BROWSE by typing "?" (or PF2).
- BROWSE displays the help-screen shown in Figure 1:
- .;
- .;
- .req "d0.req"
- .lm+3.k.nf.nj
- Screen dumped: 21-JAN-1985 06:39:56
- Image top: 0 bottom: 22
-
- +---------------------------------------------------------------------+
- |BROWSE - Browsing program |
- |Commands: |
- | Q,Z - ^&Quit\&. |
- | _? - display this message-screen |
- | __ - toggle scale/normal mode (alters arrow keys also) |
- | T,E - scroll to ^&Top\&/^&End\& of file. |
- | F,B - scroll ^&Forward\&/^&Backward\& by a full-screen. |
- | U,D - scroll ^&Up\&/^&Down\& 1/2 screen (arrow). |
- | R,L - scroll ^&Right\&/^&Left\& 1/2 screen (arrow) |
- | H - scroll left to ^&Home\&-column (in scale-mode, move cursor up |
- | I,J - (scale-mode) move cursor to next ^&tab\& stop or to next ^&end-o\&|
- | /,_\ - search (if '_\', backward) for a string |
- | N,P - search for ^&Next\&/^&Previous\& occurrence of string. |
- | W - refresh display ^&Window\& |
- | X - ^&aborts\& search/skip |
- | _<number_> - Permit H,L/R scroll by specified ^&number\& of columns, |
- | or ^&repeat\& of U,D,B,F,I or arrow keys |
- |Special: |
- | K - Copy screen to SNAPSHOT.CRT |
- | M - Toggle ^&MARK\& mode (active if /MARK option) |
- | O - Toggle ^&OVER\& mode (3 states if /OVER, else 2) |
- | V - Display current ^&Version\& |
- | _^ - Toggle ^&MARK\& (^&DEBUG\&) modes |
- |^&FL.HLP; Lines 1:23 Cols 1:71 (77)\& |
- +---------------------------------------------------------------------+
- .lm.nk.f.j
- .b2.c;Figure#1##^*Help Summary\*
- .;.stc2,1,Help Summary
- .b
- .;
- .;
- .hl Screen-Refresh
- If your screen becomes corrupted by line noise, or by unexpected
- system messages,
- you may direct BROWSE to refresh the screen.
- The W command causes BROWSE to re-read the current page and then redisplay it.
- .x Control characters>CTRL/W
- .x W, window refresh
- .x Control characters>Differences from noncontrol>CTRL/W
- A CTRL/W may be given at any time (even while entering a search target),
- and refreshes the screen without re-reading the page.
- The re-read operation is provided to make BROWSE cleaner:
- .lm+8
- .b.i-4
- o If you have directed BROWSE to display the help-screen,
- the W command will redisplay the file, rather than the help-screen.
- .b.i-4
- .x Toggle-commands>M, mark (file-address)
- o If you are using the M-command to display record marks,
- BROWSE may discover in the middle of a page that the file actually
- has records with embedded carriage control.
- The prefix jumps, from two columns of numbers, to four.
- Requiring BROWSE to read each page first to determine this case
- would make it slower.
- The W command re-reads the page and makes the prefix columns all the
- same width.
- .lm-8
- .;
- .hl Screen-Dump
- .x Control characters>CTRL/K
- .x K, copy screen
- You may obtain a copy of the screen contents by using the
- K command (also CTRL/K).
- All of the figures in this document were generated using
- this facility.
- .b
- When you issue a screen-dump command, the screen driver makes
- a copy of the current screen and writes it to a file:
- .b;########SYS_$LOGIN:SNAPSHOT.CRT
- .b;When you exit from BROWSE, this file is closed and you may print it.
- .x Highlighting>Screen dump
- Highlighting is represented in the snapshot-file by underlining.
- The time and date of the snapshot are written to the file as well.
- Each time you invoke the screen dump, BROWSE informs you of how many
- times you have done so.
- .b
- .x Control characters>CTRL/K
- .x Control characters>Differences from noncontrol>CTRL/K
- The CTRL/K screen dump is recognized at all times by BROWSE.
- The K command, of course, is not recognized during prompts.
- .;
- .hl Version
- .x Control characters>CTRL/V
- .x V, version
- Typing a V (also CTRL/V) causes BROWSE to display its version number
- in the status line.
-