NAME
mgdiff - Motif-based graphical file difference browser
SYNOPSIS
mgdiff [-toolkitoption ...] [-quit] [-file name] [-args dif-
fargs] [file1 file2]
DESCRIPTION
Mgdiff is a graphical front end to the diff command. It
permits the user to view the differences between two ASCII
files in context and, optionally, to write out a third file
which is the user-defined merging of those two files. It is
inspired by a similar program, called gdiff, which runs only
on Silicon Graphics workstations and for which source code
is not provided.
The program takes as arguments various flags (described in
the next section) and the names of two files to compare.
Either filename (but not both) may be given as '-' to use
standard input instead.
The resulting display consists mostly of two panes of text;
the one on the left is the first file specified and the one
on the right is the second file specified. Between and
below the text panes are scrollbars that permit changing the
visible portions of the two files being compared. In addi-
tion, the program implements the Scrolled Region recommenda-
tions of Section 2.3.4 of the OSF/Motif Style Guide (release
1.1), meaning that the arrow and paging keys will work to
scroll as well. Above each text pane is the name of the
file in that text pane and the line number in the file which
is being displayed.
The text in each of the text panes is divided into blocks of
lines which are color-coded with one of five different
colors. This indicates that the block:
differs between the two files
is identical between the two files
has been inserted in one file or the other
is for display purposes (to match an inserted block in
the other file)
has been selected by the user (for writing to a merged
file)
These colors can be modified by the user via X resources;
see the RESOURCES section of this manual page. A legend
display of the colors and their meanings is available using
the Help menu.
On the right-hand side of the display is an overview area;
this shows the files in their entirety. The sliders in the
overview area track the lines being displayed in the text
panes.
At the top of the display is a Motif menu bar; those func-
tions are discussed in the MENUS section of this manual
page.
COMMAND LINE OPTIONS
-toolkitoption
These are the standard options accepted by all
applications that use the X Toolkit Intrinsics. See
the OPTIONS section in the X(1) manual page.
-quit This option sets the resource Mgdiff.quitIfSame to
"true". This will cause the program to exit immedi-
ately without bringing up a window if the two files
have no differences (as determined by the diff com-
mand).
-args diffargs
This option sets the resource Mgdiff.diffArgs to the
value of the diffargs argument. These flags are
passed to the diff command that actually computes
the differences between the two files. Since any
argument can be passed, it is possible to specify
flags that cause the diff command to fail or to gen-
erate output in a different format that will cause
mgdiff to fail. For most versions of diff, only
three flags make any sense. The first is '-b'; this
causes diff to ignore trailing blanks (spaces and
tabs) and to treat all other strings of blanks as
equivalent. The second flag is '-w'; this ignores
blanks and treats strings of blanks as equivalent.
The last flag is '-i'; this ignores case when com-
paring letters.
-file name
This command sets the resource Mgdiff.filename to
the value of the name argument. mgdiff uses this
string to display over a file read from standard
input.
MENUS
The menubar contains the following menu topics as Cascade-
Buttons: File, View, Select, Options and Help. The rest of
this section discusses each menu entry, showing it's name
and accelerator, if any.
File
This pulldown menu controls file access:
Open... Ctrl+O
Brings up the "Open Files" FileSelectionDialog to
allow the user to open two files for comparison.
Open Left... Ctrl+L
Brings up the "Open File" FileSelectionDialog to
allow the user to specify a file to open and compare
with the already opened right-hand file.
Open Right... Ctrl+R
Brings up the "Open File" FileSelectionDialog to
allow the user to specify a file to open and compare
with the already opened left-hand file.
Save As... Ctrl+S
Brings up the "Save File" FileSelectionDialog to
allow the user to specify an output file for writing
the merged file; this is an application modal dialog.
The program will allow the user to overwrite an
existing file but pops up a QuestionDialog to allow
the user to cancel the operation if desired. If
there are any unselected areas of difference between
the two files the user is notified via an ErrorDialog
and the save operation is canceled.
Exit Ctrl+C
Exits the program immediately.
View
This pulldown menu contains commands for moving through the
files.
Previous Ctrl+P
Scrolls both file views so that the previous area of
difference is Mgdiff.linesOfContext lines from the
top of the application window.
Next Ctrl+N
Scrolls both file views so that the next area of
difference is Mgdiff.linesOfContext lines from the
top of the application window.
Next Unselected Ctrl+U
Scrolls both file views so that the next unselected
area of difference is Mgdiff.linesOfContext lines
from the top of the application window.
Select
The two files being compared can be optionally merged into
one file. To do this, the user must select for each area of
difference between the two files which version should be
written to the merged file. The menu entries in this pull-
down menu allow the user to select or unselect differences
in groups rather than individually.
Left All
For all areas of difference between the two files
select the left-hand file version.
Right All
For all areas of difference between the two files
select the right-hand file version.
Unselect All
Unselects all areas of difference in both files.
Options
This pulldown menu controls miscellaneous appearance and/or
behavior options.
Overview Ctrl+W
This menu entry toggles the presence of the overview
area on the right-hand side of the application win-
dow. The default value for this toggle is controlled
by a resource, Mgdiff.overview, which is described in
the RESOURCES section.
Horizontal Scrollbar Ctrl+H
This menu entry toggles the presence of the horizon-
tal scrollbar at the bottom of the application
window. The default value for this toggle is con-
trolled by a resource, Mgdiff.horzScrollbar, which is
described in the RESOURCES section.
Drag Scroll Ctrl+D
This menu entry toggles the behaviour of the
scrollbars in the application window. When set,
dragging the slider of a scrollbar results in a
immediate change in the view of the text being com-
pared. When unset, the view is only changed at the
end of a slider drag (when the mouse button is
released.) This setting might be preferred on a
slower X server. The default value for this toggle
is controlled by a resource, Mgdiff.dragScroll, which
is described in the RESOURCES section.
Help
This pulldown menu displays commands for obtaining help on
or information about mgdiff.
Version... Ctrl+V
Brings up an InformationDialog with author and ver-
sion information.
Manual Page... Ctrl+M
Brings up a DialogShell with a ScrolledText widget
containing this manual page. The command for gen-
erating this is customizable via a resource,
Mgdiff.manCommand, which is described in the
RESOURCES section.
Color Legend... Ctrl+G
Brings up a DialogShell which summarizes the use of
color in encoding the types of differences between
the two files being compared.
OTHER DISPLAYS/CONTROLS
You can move directly to a particular spot in the two files
by using BDrag in the overview area.
The program uses what the OSF/Motif Style Guide calls "mul-
tiple selection" to select individual blocks for writing to
a merged file. Clicking BSelect on an unselected block adds
it to the list of selected blocks. Clicking BSelect on a
selected block removes it from the list of selected blocks.
In addition, Clicking BSelect on an unselected block which
is opposite a selected block (in the other text panes)
removes the selected block from the list of selected blocks.
The numbers in the small boxes next to the file names are
the line numbers of the lines at the top of the text panes.
WIDGETS
What follows is the hierarchy of Motif widgets, as generated
by editres(1). The hierarchical structure of the widget
tree is reflected in the indentation. Each line consists of
the widget class name followed by the widget instance name.
This information might be useful if you wish to customize
the appearance of the program via resource settings.
Mgdiff mgdiff
XmMainWindow mainw
XmSeparatorGadget MainWinSep1
XmSeparatorGadget MainWinSep2
XmSeparatorGadget MainWinSep3
XmRowColumn menubar
XmCascadeButtonGadget button_0
XmCascadeButtonGadget button_1
XmCascadeButtonGadget button_2
XmCascadeButtonGadget button_3
XmCascadeButtonGadget button_4
XmMenuShell popup_file_menu
XmRowColumn select_menu
XmPushButtonGadget button_0
XmPushButtonGadget button_1
XmSeparatorGadget separator_0
XmPushButtonGadget button_2
XmRowColumn file_menu
XmPushButtonGadget button_0
XmPushButtonGadget button_1
XmPushButtonGadget button_2
XmPushButtonGadget button_3
XmSeparatorGadget separator_0
XmPushButtonGadget button_4
XmRowColumn options_menu
XmToggleButtonGadget button_0
XmToggleButtonGadget button_1
XmToggleButtonGadget button_2
XmRowColumn help_menu
XmPushButtonGadget button_0
XmPushButtonGadget button_1
XmPushButtonGadget button_2
XmRowColumn view_menu
XmPushButtonGadget button_0
XmPushButtonGadget button_1
XmPushButtonGadget button_2
XmForm form1
XmFrame frame1
XmForm form3
XmScrollBar sbl
XmDrawingArea dam
XmScrollBar sbr
XmFrame frame2
XmForm form4
XmForm form2
XmScrollBar sb
XmForm form21
XmFrame frame3
XmLabel fnamel
XmFrame frame31
XmTextField linenuml
XmForm form22
XmFrame frame4
XmLabel fnamer
XmFrame frame41
XmTextField linenumr
XmDrawingArea textl
XmDrawingArea textr
XmScrollBar sbh
XmDialogShell version_popup
XmMessageBox version
XmLabelGadget symbol
XmLabelGadget
XmSeparatorGadget separator
XmPushButtonGadget OK
XmPushButtonGadget Cancel
XmPushButtonGadget Help
XmDialogShell manualpage_popup
XmForm manualpage
XmPanedWindow pane
XmScrolledWindow help_textSW
XmScrollBar vbar
XmText help_text
XmForm form2a
XmPushButton OK
XmSash sash
XmSeparatorGadget separator
XmSash sash
XmSeparatorGadget separator
XmDialogShell legend_popup
XmForm legend
XmPanedWindow pane
XmRowColumn rc
XmLabel label1
XmLabel label2
XmLabel label3
XmLabel label4
XmLabel label5
XmForm form2a
XmPushButton OK
XmSash sash
XmSeparatorGadget separator
XmSash sash
XmSeparatorGadget separator
XmDialogShell werror_popup
XmMessageBox werror
XmLabelGadget symbol
XmLabelGadget
XmSeparatorGadget separator
XmPushButtonGadget OK
XmPushButtonGadget Cancel
XmPushButtonGadget Help
X RESOURCES
Mgdiff.diffForeground: black
Mgdiff.diffBackground: yellow
These colors are for blocks which differ between files.
Mgdiff.sameForeground: black
Mgdiff.sameBackground: grey
These colors are for blocks which are identical between
files.
Mgdiff.insertForeground: black
Mgdiff.insertBackground: orange
These colors are for blocks which have been inserted in one
file.
Mgdiff.blankForeground: black
Mgdiff.blankBackground: grey66
These colors are for blocks which are for display purposes.
Mgdiff.selectForeground: black
Mgdiff.selectBackground: light slate blue
These colors are for blocks which have been selected by the
user.
Mgdiff.font: 7x13bold
Font for displaying text blocks.
Mgdiff.dragScroll: true
Set to true if scrollbar dragging should cause immediate
changes in the viewed text, and false if the view should
only change after the scrollbar has been moved.
Mgdiff.overview: true
Set to true if the file overview section should appear.
Mgdiff.horzScrollbar: true
Set to true if the horizontal scrollbar should appear.
Mgdiff.linesOfContext: 3
Number of lines that should appear above a difference block
gotten to using the Previous or Next commands. Should be
greater or equal to zero.
Mgdiff.manCommand: (man mgdiff | col -b) 2>&1
The command (or pipeline) used to produce a formatted manual
page without escape codes.
Mgdiff.diffCommand: diff
The diff(1) compatible command to use for calculating
differences between text files.
Mgdiff.diffArgs:
The arguments to be provided to the diff command. This
resource can also be set via the -args command line option.
Mgdiff.quitIfSame: false
If the two files have no differences (as determined by the
diff command) then exit immediately without bringing up a
window. This resource can also be set to "true" via the
-quit command line option.
Mgdiff.filename: (stdin)
mgdiff uses this string to display over a file read from
standard input. This resource can also be set via the -file
command line option.
DIAGNOSTICS
Returns the exit status generated by the diff command. This
is usually 0 for no differences, 1 for some differences and
2 for errors.
SEE ALSO
diff(1), X(1)
RESTRICTIONS
Using BDrag in the overview area doesn't work well when drag
scrolling is turned off.
Doesn't support monochrome displays.
Input lines longer than BUFSIZ (see /usr/include/stdio.h)
are silently truncated.
The code for parsing and passing arguments to the diff com-
mand assumes arguments are delimited by white space and does
not do any quote processing.
COPYRIGHT
Copyright (c) 1994, Daniel Williams
See X (1) for a full statement of rights and permissions.
AUTHOR
Daniel Williams (dan@sass.com)
ACKNOWLEDGEMENTS
To Andrew C. Myers for writing gdiff.
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