Solved

Checking if a string contains a letter in ksh

Posted on 2004-04-26
8
3,557 Views
Last Modified: 2007-12-19
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

0
Comment
Question by:r47463
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
  • 2
  • 2
  • +1
8 Comments
 

Author Comment

by:r47463
ID: 10923312
PS rather than just letters, I would like any non-numeric characters to be invalid.
0
 
LVL 28

Expert Comment

by:FishMonger
ID: 10924787
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
0
 
LVL 28

Expert Comment

by:FishMonger
ID: 10924822
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
0
Get 15 Days FREE Full-Featured Trial

Benefit from a mission critical IT monitoring with Monitis Premium or get it FREE for your entry level monitoring needs.
-Over 200,000 users
-More than 300,000 websites monitored
-Used in 197 countries
-Recommended by 98% of users

 
LVL 9

Expert Comment

by:bhagyesht
ID: 10925105
Hi r47463,
use isnumeric function to determine whether its a number or not

Cheers!
0
 
LVL 45

Expert Comment

by:sunnycoder
ID: 10925274
[!0-9] represents all non numeric characters .. 0-9 is the range for numeric characters and ! is negation
0
 
LVL 9

Expert Comment

by:bhagyesht
ID: 10926896
sorry wrongly interpreted it for VB.

Regards,
Bhagyesh
0
 
LVL 45

Accepted Solution

by:
sunnycoder earned 40 total points
ID: 10927170
>At the moment I don't know how to check when a string has both a number and a letter; it just crashes out.

execute this

echo $u | grep "[^0-9]" >dev/null
then check for value of $? ... If 1 then it was composed of characters from 0-9

if [ $? -eq 1 ]
then
          echo valid
else
          echo invalid
fi
0
 

Author Comment

by:r47463
ID: 10932270
Superb thanks!
0

Featured Post

What Is Transaction Monitoring and who needs it?

Synthetic Transaction Monitoring that you need for the day to day, which ensures your business website keeps running optimally, and that there is no downtime to impact your customer experience.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

A short article about a problem I had getting the GPS LocationListener working.
A short article about problems I had with the new location API and permissions in Marshmallow
In this fourth video of the Xpdf series, we discuss and demonstrate the PDFinfo utility, which retrieves the contents of a PDF's Info Dictionary, as well as some other information, including the page count. We show how to isolate the page count in a…
Six Sigma Control Plans

729 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question