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Top Forums Shell Programming and Scripting Is there any way to makesure that the input from the user is all numbers? Post 15097 by XXXXXXXXXX on Sunday 10th of February 2002 01:14:16 PM
Old 02-10-2002
Quote:
Originally posted by Jimbo
if expr "$answer" : "[0-9]*$" > /dev/null ; then
echo 'all digits'
else
echo 'NOT all digits'
fi
what does the *$ after the [0-9] means ?
and what does > /dev/null means
i know that if i never put the > /dev/null , if all the user input is digits, it will display out now many digits are there.
can explain to me what does these means ?

thank you
XXXXXXXXXX
 

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CTYPE_ALNUM(3)								 1							    CTYPE_ALNUM(3)

ctype_alnum - Check for alphanumeric character(s)

SYNOPSIS
bool ctype_alnum (string $text) DESCRIPTION
Checks if all of the characters in the provided string, $text, are alphanumeric. PARAMETERS
o $text - The tested string. RETURN VALUES
Returns TRUE if every character in $text is either a letter or a digit, FALSE otherwise. EXAMPLES
Example #1 A ctype_alnum(3) example (using the default locale) <?php $strings = array('AbCd1zyZ9', 'foo!#$bar'); foreach ($strings as $testcase) { if (ctype_alnum($testcase)) { echo "The string $testcase consists of all letters or digits. "; } else { echo "The string $testcase does not consist of all letters or digits. "; } } ?> The above example will output: The string AbCd1zyZ9 consists of all letters or digits. The string foo!#$bar does not consist of all letters or digits. NOTES
Note If an integer between -128 and 255 inclusive is provided, it is interpreted as the ASCII value of a single character (negative val- ues have 256 added in order to allow characters in the Extended ASCII range). Any other integer is interpreted as a string contain- ing the decimal digits of the integer. SEE ALSO
ctype_alpha(3), ctype_digit(3), setlocale(3). PHP Documentation Group CTYPE_ALNUM(3)
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