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making sure my string is [a-z] only

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# 1  
Old 04-24-2009
making sure my string is [a-z] only
Hi there

I am trying to figure out how I can validate my string to ensure that it is consists of only lower case alpha chrataters [a-z]

but for some reason whatever I do, it seems to come back with 'true'

I have tried



Code:
		if [[ $VAR="[^a-z+]" ]] ; then
		    echo "yes its fine"
		else
		     echo "nope"
		fi

and ive also tried (amongst other variations)


Code:
	  case $VAR in
		[a-z]) echo "string is ok" ;;
		*) 	  echo "string is not ok" ;;
		  esac

both of these return true whatever i do


Is there something im doing here thats wrong

Cheers
# 2  
Old 04-24-2009
Try...
Code:
$ for VAR in Aa A a
> do
>  if [[ $VAR = $(echo $VAR|tr -dc '[a-z]') ]] && [[ -n $VAR ]]
>  then
>      echo $VAR is ok
>  else
>      echo $VAR is not ok
>  fi
> done
Aa is not ok
A is not ok
a is ok
$

# 3  
Old 04-24-2009
Code:
if [[ $VAR = *([a-z]) ]]; then
  echo "yes its fine"
else
  echo "nope"
fi

*([a-z]) allows empty string. If an empty string is not fine, then use +([a-z]).
# 4  
Old 04-24-2009
With case:

Code:
case $var in 
  "" | *[!a-z]* ) echo invalid ;; 
              * ) echo ok ;;
esac

# 5  
Old 04-24-2009
Quote:
Originally Posted by colemar
Code:
if [[ $VAR = *([a-z]) ]]; then
  echo "yes its fine"
else
  echo "nope"
fi

*([a-z]) allows empty string. If an empty string is not fine, then use +([a-z]).
The original poster wants to ensure that the string contains only lower case alpha chrataters ...
# 6  
Old 04-24-2009
Quote:
Originally Posted by radoulov
With case:

Code:
case $var in 
  "" | *[!a-z]* ) echo invalid ;; 
              * ) echo ok ;;
esac


Thanks for your help (all of you)

radoulov ... It still seems to have problems with capital letters
for example, look at this output from your case statement above

Code:
peter
ok

peter1
invalid

Peter
ok

PETER
ok


The capitals seem to be a problem ... thanks for your help though
# 7  
Old 04-24-2009
It's because of your locale, try setting LANG=C for the duration of the script:

Code:
% cat s
case $var in
  "" | *[!a-z]* ) echo invalid ;;
              * ) echo ok ;;
esac
% var=A
% LANG=it.UTF-8 . s
ok
% LANG=C . s
invalid

Last edited by radoulov; 04-24-2009 at 06:51 AM.. Reason: LANG is sufficient ...
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