Match on a range of numbers

Shell Programming and Scripting
1

Hi,
I'm trying to match a filename that could be called anything from vout001 to vout252 and was trying to do a small test but I'm not getting the result I thought I would..

Can some one tell me what I'm doing wrong?

*****@********[/home/aiw1]>echo $mynumber                                                         
vout123
*****@********[/home/aiw1]>if [ $mynumber == 'vout[0...252]' ]                                      
> then
> echo 't'
> else
> echo 'f'
> fi
f
2

Ranges are charracter classes in regular expressions, not integer values, the range you created is 0..252 ie. the set (0,1,2,5,2) however ranges need to be used in a suitable tool rather than directly in the shell
One, horrendously complex, way of doing it would be to capture the digits and assess them separately like below, there is probably a much neater solution though...

$ myfile=vout123
$ export myfile
$ perl -e 'if ($ENV{myfile}=~/vout(\d+)/ && $1 >0 && $1 <253){print "t\n";}'
t
$
3

There are several different kinds of confusion in there.

You cannot use == inside [ ] brackets, it needs [[ ]] brackets.

And == does not understand number ranges anyway. It understands characters.

Try a case statement:

case "$VAR" in
abcd[0-9])  echo stuff ;;
abcd[1-9][0-9])  echo stuff ;;
abcd1[0-9][0-9]) echo stuff ;;
abcd2[1-4][0-9]) echo stuff ;;
abcd25[0-2]) echo stuff ;;
*) echo "not matched" ;;
esac

Or you could try stripping out the number first and just comparing that.

1 Like
4

Hello,

One more approach with awk .

echo $VAR | awk '/[a-z]{3}[0-9]{3}/ {print "Matched"}; /![a-z]{3}[0-9]{3}/ {print "NOT matched"}'

where var variable have the values.

Thanks,
R. Singh

5

Perhaps like this:

$ echo $mynumber
vout123
$ if [ ${mynumber#????} -ge 0 ] && [ ${mynumber#????} -le 252 ]
> then
>    echo 't'
> else
>    echo 'f'
> fi
t