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Full Discussion: Assigning Variables
Top Forums Shell Programming and Scripting Assigning Variables Post 302891115 by Scrutinizer on Tuesday 4th of March 2014 02:42:08 AM
Old 03-04-2014
The first means:
Quote:
${parameter-[word]}
Use Default Values. If parameter is unset, the expansion of word is substituted. Otherwise, the value of parameter is substituted.
The second is a regular variable assignment. The quotes are not necessary:

Both variables are exported.

To give an example:
Code:
$ echo "$var"

$ var=${var-foo}
$ echo "$var"
foo
$ var=
$ var=${var-foo}
$ echo "$var"

$ unset var
$ echo "$var"

$ var=${var-foo}
$ echo "$var"
foo


Last edited by Scrutinizer; 03-04-2014 at 04:00 AM..
This User Gave Thanks to Scrutinizer For This Post:
 

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scrl(3XCURSES)						  X/Open Curses Library Functions					    scrl(3XCURSES)

NAME
scrl, scroll, wscrl - scroll a window SYNOPSIS
cc [ flag... ] file... -I /usr/xpg4/include -L /usr/xpg4/lib -R /usr/xpg4/lib -lcurses [ library... ] c89 [ flag... ] file... -lcurses [ library... ] #include <curses.h> int scrl(int n); int scroll(WINDOW *win); int wscrl(WINDOW *win, int n); PARAMETERS
n number and direction of lines to scroll win pointer to the window in which to scroll DESCRIPTION
The scroll() function scrolls the window win up one line. The current cursor position is not changed. The scrl() and wscrl() functions scroll the window stdscr or win up or down n lines, where n is a positive (scroll up) or negative (scroll down) integer. The scrollok(3XCURSES) function must be enabled for these functions to work. RETURN VALUES
On success, these functions return OK. Otherwise, they return ERR. ERRORS
None. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ |MT-Level |Unsafe | +-----------------------------+-----------------------------+ SEE ALSO
clearok(3XCURSES), libcurses(3XCURSES), attributes(5), standards(5) SunOS 5.10 5 Jun 2002 scrl(3XCURSES)
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