asked on

Checking if a string contains a letter in ksh

Hi, I'd like to check a string for the presence of letters.

E.g.

"123" valid
"abc" invalid
"123abc" invalid

At the moment I don't know how to check when a string has both a number and a letter; it just crashes out.

My current code is as follows:

i=1
until (test $i -gt 4)
do
echo "$arg1"|cut -f$i -d'.'|read octet
if [[ "$octet" = +([a-z]) ]]
then
echo "Error - invalid IP address entered"
IPvalid=0
i=4
else
if [[ $octet -ge 0 && $octet -le 255 ]]
then
IPvalid=1
else
echo "Error - invalid IP address entered"
IPvalid=0
i=4
fi
fi
i=`expr $i + 1`
done

Thanks

r47463

ASKER

PS rather than just letters, I would like any non-numeric characters to be invalid.

FishMonger

Would you be interested in using Perl instead of ksh?

#!/usr/bin/perl -w

use strict;
use Validate::Net;

my $good = '123.1.23.123';
my $bad1 = '123.432.21.12';
my $bad2 = 'abc.232.21.12';

foreach ( $good, $bad1, $bad2 ) {
if ( Validate::Net->ip( $_ ) ) {
print "'$_' is a valid ip\n\n";
}
else {
print "'$_' is not a valid ip address because:\n";
print Validate::Net->reason . "\n\n";
}
}

-- outputs --
'123.1.23.123' is a valid ip

'123.432.21.12' is not a valid ip address because:
The maximum value for an ip element is 255

'abc.232.21.12' is not a valid ip address because:
Does not fit the basic dotted quad format for an ip

FishMonger

That code sample is from the CPAN documentation for the Validate::Net module.

http://search.cpan.org/~adamk/Validate-Net-0.5/lib/Validate/Net.pm

bhagyesht

Hi r47463,
use isnumeric function to determine whether its a number or not

Cheers!

sunnycoder

[!0-9] represents all non numeric characters .. 0-9 is the range for numeric characters and ! is negation

bhagyesht

sorry wrongly interpreted it for VB.

Regards,
Bhagyesh

ASKER CERTIFIED SOLUTION

sunnycoder

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