Dialog
is a program that will let you to present a variety of questions or
display messages using dialog boxes from a shell script.
These types of dialog boxes are implemented
(though not all are necessarily compiled into dialog):
calendar,
checklist,
fselect,
gauge,
infobox,
inputbox,
menu,
msgbox (message),
password,
radiolist,
tailbox,
tailboxbg,
textbox,
timebox, and
yesno (yes/no).
You can put more than one dialog box into a script:
-
Use the --and-widget token to force Dialog to proceed to the next
dialog unless you have pressed ESC to cancel, or
-
Simply add the tokens for the next dialog box, making a chain.
Dialog stops chaining when the return code from a dialog is nonzero,
e.g., Cancel or No.
OPTIONS
Common Options
--aspect ratio
This gives you some control over the box dimensions when using auto
sizing (specifying 0 for height and width).
It represents width / height.
The default is 9, which means 9 characters wide to every 1 line high.
--backtitle backtitle
Specifies a
backtitle
string to be displayed on the backdrop, at the top of the screen.
--beep
Sound the audible alarm
each time the screen is refreshed.
--beep-after
Beep if input is interrupted, e.g., by a control/C.
--begin
y x
Specify the position of the upper left corner of a dialog box on the screen.
--cancel-label string
Override the label used for "Cancel" buttons.
--clear
The screen will be cleared to the
screen attribute
on exit.
This may be used alone, without other options.
--cr-wrap
Interpret embedded newlines in the dialog text as a newline on the screen.
Otherwise, dialog
will only wrap lines where needed to fit inside the text box.
Even though you can control line breaks with this,
dialog will still wrap any lines that are too long for the width of the box.
Without cr-wrap, the layout of your text may be formatted to look nice
in the source code of your script without affecting the way it will
look in the dialog.
--create-rc file
When
dialog
supports run-time configuration,
this can be used to dump a sample configuration file to the file specified
by
file.
--defaultno
Make the default value of the
yes/no
box a
No.
--default-item string
Set the default item in a menu box.
Normally the first item in the box is the default.
--help
Prints the help message to standard error.
The help message is printed if no options are given.
--help-button
Show a help-button after ok/cancel buttons.
--help-label
string
Override the label used for "Help" buttons.
--ignore
Ignore options that dialog
does not recognize.
Some well-known ones such as "--icon" are ignored anyway,
but this is a better choice for compatibility with other implementations.
--item-help
Interpret the tags data for checklist, radiolist and menuboxes
adding a column which is displayed in the bottom line of the
screen, for the currently selected item.
--max-input
size
Limit input strings to the given size.
If not specified, the limit is 2000.
--no-kill
Tells
dialog
to put the
tailboxbg
box in the background,
printing its process id to standard error.
SIGHUP is disabled for the background process.
--no-cancel
--nocancel
Suppress the "Cancel" button in checklist, inputbox and menubox modes.
A script can still test if the user pressed the ESC key to cancel to quit.
--no-shadow
Suppress shadows that would be drawn to the right and bottom of each dialog box.
--ok-label
string
Override the label used for "OK" buttons.
--print-maxsize
Print the maximum size of dialog boxes, i.e., the screen size,
to the standard error.
This may be used alone, without other options.
--print-size
Prints the size of each dialog box to standard error.
--print-version
Prints dialog
's version to standard error.
This may be used alone, without other options.
--separate-output
For checklist widgets, output result one line at a time, with no quoting.
This facilitates parsing by another program.
--separate-widget
string
Specify a string that will separate the output on standard error from
each widget.
This is used to simplify parsing the result of a dialog with several widgets.
If this option is not given,
the default separator string is a tab character.
--shadow
Draw a shadow to the right and bottom of each dialog box.
--size-err
Check the resulting size of a dialog box before trying to use it,
printing the resulting size if it is larger than the screen.
(This option is obsolete, since all new-window calls are checked).
--sleep
secs
Sleep (delay) for the given number of seconds after processing a dialog box.
--stderr
Direct output to the standard error.
This is the default, since curses normally writes screen updates to
the standard output.
--stdout
Direct output to the standard output.
--tab-correct
Convert each tab character to one or more spaces.
Otherwise, tabs are rendered according to the curses library's interpretation.
--tab-len
n
Specify the number of spaces that a tab character occupies if the
"
--tab-correct"
option is given.
The default is 8.
--timeout secs
Timeout (exit with error code)
if no user response within the given number of seconds.
--title title
Specifies a
title
string to be displayed at the top of the dialog box.
--trim
eliminate leading blanks,
trim literal newlines and repeated blanks from message text.
--version
Same as "--print-version
".
Box Options
All dialog boxes have at least three parameters:
text
the caption or contents of the box.
height
the height of the dialog box.
width
the width of the dialog box.
Other parameters depend on the box type.
--calendar text height width day month year
A
calendar
box displays month, day and year in separately adjustable windows.
If the values for day, month or year are missing or negative,
the current date's corresponding values are used.
You can increment or decrement any of those using the
left-, up-, right- and down-arrows.
Use tab or backtab to move between windows.
If the year is given as zero, the current date is used as an initial value.
On exit, the date is printed in the form day/month/year.
--checklist text height width list-height [ tag item status ] ...
A
checklist
box is similar to a
menu
box; there are
multiple entries presented in the form of a menu.
Instead of choosing
one entry among the entries, each entry can be turned on or off by the user.
The initial on/off state of each entry is specified by
status.
On exit, a list of the
tag
strings of those entries that are turned on will be printed on
stderr.
--fselect filepath height width
The file-selection dialog displays a text-entry window in which you can type
a filename (or directory), and above that two windows with directory
names and filenames.
Here
filepath
can be a filepath in which case the file and directory windows
will display the contents of the path and the text-entry window will contain
the preselected filename.
Use tab or arrow keys to move between the windows.
Within the directory or filename windows, use the up/down arrow keys
to scroll the current selection.
Use the space-bar to copy the current selection into the text-entry
window.
Typing any printable characters switches focus to the text-entry window,
entering that character as well as scrolling the directory and filename
windows to the closest match.
Use a carriage return or the "OK" button to accept the current value
in the text-entry window, or the "Cancel" button to cancel.
--gauge text height width [percent]
A
gauge
box displays a meter along the bottom of the box.
The meter indicates the percentage.
New percentages are read from
standard input, one integer per line.
The meter is updated
to reflect each new percentage.
If stdin is XXX, then subsequent
lines up to another XXX are used for a new prompt.
The gauge exits when EOF is reached on stdin.
The percent value denotes the initial percentage shown in the meter.
If not specified, it is zero.
--infobox text height width
An
info box is basically a message box.
However, in this case, dialog
will exit immediately after displaying the message to the user.
The screen is not cleared when dialog
exits, so that the message will remain on the screen until the calling
shell script clears it later.
This is useful when you want to inform
the user that some operations are carrying on that may require some
time to finish.
--inputbox text height width [init]
An
input
box is useful when you want to ask questions that
require the user to input a string as the answer.
If init is supplied
it is used to initialize the input string.
When entering the
string, the
BACKSPACE
key can be used to correct typing errors.
If the input string is longer than
can fit in the dialog box, the input field will be scrolled.
On exit, the input string will be printed on
stderr.
--menu text height width menu-height [ tag item ] ...
As its name suggests, a
menu
box is a dialog box that can be used to present a list of choices in
the form of a menu for the user to choose.
Choices are displayed in the order given.
Each menu entry consists of a tag string and an item string.
The tag
gives the entry a name to distinguish it from the other entries in the
menu.
The item is a short description of the option that the entry represents.
The user can move between the menu entries by pressing the
UP/DOWN keys, the first letter of the tag
as a hot-key, or the number keys
1-9. There are
menu-height
entries displayed in the menu at one time, but the menu will be
scrolled if there are more entries than that.
When dialog exits, the tag
of the chosen menu entry will be printed on
stderr.
If the --help-button option is given, the corresponding help
text will be printed if the user selects the help button.
--msgbox text height width
A
message box is very similar to a yes/no box.
The only difference between a message box and a yes/no
box is that a message box has only a single OK button.
You can use this dialog box to display any message you like.
After reading the message, the user can press the ENTER key so that
dialog will exit and the calling shell script can continue its operation.
--passwordbox text height width [init]
A
password
box is similar to an input box, except that the text the user
enters is not displayed.
This is useful when prompting for passwords or other
sensitive information.
Be aware that if anything is passed in "init", it
will be visible in the system's process table to casual snoopers.
Also, it
is very confusing to the user to provide them with a default password they
cannot see.
For these reasons, using "init" is highly discouraged.
--radiolist text height width list-height [ tag item status ] ...
A
radiolist
box is similar to a
menu
box.
The only difference is
that you can indicate which entry is currently selected, by setting its
status to on.
--tailbox file height width
Display text from a file in a dialog box, as in a "tail -f" command.
--tailboxbg file height width
Display text from a file in a dialog box as a background task,
as in a "tail -f &" command.
Dialog treats the background task specially if there are other
widgets (--and-widget
) on the screen concurrently.
Until those widgets are closed (e.g., an "OK"),
dialog will perform all of the tailboxbg widgets in the same process,
polling for updates.
You may use a tab to traverse between the widgets on the screen,
and close them individually, e.g., by pressing ENTER.
Once the non-tailboxbg widgets are closed, dialog forks a copy of itself
into the background, and prints its process id if the --no-kill option
is given.
NOTE:
Older versions of dialog forked immediately and attempted to
update the screen individually.
Besides being bad for performance,
it was unworkable.
Some older scripts may not work properly with the polled scheme.
--textbox file height width
A
text
box lets you display the contents of a text file in a dialog box.
It is like a simple text file viewer.
The user can move through the file by using the
UP/DOWN, PGUP/PGDN
and HOME/END keys available on most keyboards.
If the lines are too long to be displayed in the box, the
LEFT/RIGHT
keys can be used to scroll the text region horizontally.
For more convenience,
forward and backward searching functions are also provided.
--timebox text height [width hour minute second]
A dialog is displayed which allows you to select hour, minute and second.
If the values for hour, minute or second are missing or negative,
the current date's corresponding values are used.
You can increment or decrement any of those using the
left-, up-, right- and down-arrows.
Use tab or backtab to move between windows.
On exit, the result is printed in the form hour:minute:second.
--yesno text height width
A
yes/no dialog box of
size height rows by width columns will be displayed.
The string specified by
text
is displayed inside the dialog box.
If this string is too long to fit
in one line, it will be automatically divided into multiple lines at
appropriate places.
The
text
string can also contain the sub-string
"\n"
or newline characters
`\n'
to control line breaking explicitly.
This dialog box is useful for
asking questions that require the user to answer either yes or no.
The dialog box has a
Yes
button and a
No
button, in which the user can switch between by pressing the
TAB key.
RUN-TIME CONFIGURATION
1.
Create a sample configuration file by typing:
"dialog --create-rc <file>"
2.
At start,
dialog
determines the settings to use as follows:
a)
if environment variable
DIALOGRC
is set, its value determines the name of the configuration file.
b)
if the file in (a) is not found, use the file
$HOME/.dialogrc
as the configuration file.
c)
if the file in (b) is not found, try using the GLOBALRC file determined at
compile-time, i.e., /etc/dialogrc.
d)
if the file in (c) is not found, use compiled in defaults.
3.
Edit the sample configuration file and copy it to some place that
dialog
can find, as stated in step 2 above.
ENVIRONMENT
DIALOGRC
Define this variable if you want to specify the name of the configuration file
to use.
DIALOG_CANCEL
DIALOG_ERROR
DIALOG_ESC
DIALOG_OK
Define any of these variables to change the exit code on Cancel (1),
error (-1), ESC (255) or Ok (0).
Normally shell scripts cannot distinguish between -1 and 255.
FILES
$HOME/.dialogrc
default configuration file
DIAGNOSTICS
Exit status is subject to being overridden by environment variables.
Normally they are:
0
if
dialog is exited by pressing the Yes or OK
button.
1
if the
No or Cancel
button is pressed.
-1
if errors occur inside dialog
or dialog is exited by pressing the ESC key.