11-24-2006
test Null variable
hi forum
i beginning with script and i want test un null variable in a schell
i just don t know the syntax here is a litle example
y=test
echo $y
unset y
echo $y (so here Y = Null)
if Y=Null
then
echo "y is null"
exit
fi
i have try
if [ !$y ]
but i have the error
test: argument expected
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LEARN ABOUT DEBIAN
colorreset
COLORS(3) libbash colors Library Manual COLORS(3)
NAME
colors -- libbash library for setting tty colors.
SYNOPSIS
colorSet <color>
colorReset
colorPrint [<indent>] <color> <text>
colorPrintN [<indent>] <color> <text>
DESCRIPTION
General
colors is a collection of functions that make it very easy to put colored text on tty.
The function list:
colorSet Sets the color of the prints to the tty to COLOR
colorReset Resets current tty color back to normal
colorPrint Prints TEXT in the color COLOR indented by INDENT (without adding a newline)
colorPrintN The same as colorPrint, but trailing newline is added
Detailed interface description follows.
Available colors:
Green
Red
Yellow
White
The color parameter is non-case-sensitive (i.e. RED, red, ReD, and all the other forms are valid and are the same as Red).
FUNCTIONS DESCRIPTIONS
colorSet <color>
Sets the current printing color to color.
colorReset
Resets current tty color back to normal.
colorPrint [<indent>] <color>
Prints text using the color color indented by indent (without adding a newline).
Parameters:
<indent>
The column to move to before start printing. This parameter is optional. If ommitted - start output from current cursor position.
<color>
The color to use.
<color>
The text to print.
colorPrintN [<indent>] <color>
The same as colorPrint, except a trailing newline is added.
EXAMPLES
Printing a green 'Hello World' with a newline:
Using colorSet:
$ colorSet green
$ echo 'Hello World'
$ colorReset
Using colorPrint:
$ colorPrint 'Hello World'; echo
Using colorPrintN:
$ colorPrintN 'Hello World'
AUTHORS
Hai Zaar <haizaar@haizaar.com>
Gil Ran <gil@ran4.net>
SEE ALSO
ldbash(1), libbash(1)
Linux Epoch Linux