Non Numeric Check

if [ -z $(echo $var | grep [0-9]) ]; then echo "NON NUMERIC"; fi
use to execute a block of code only if $var is numeric

2
2009-06-04 07:41:26

What Others Think

Hmm... It doesn't really check if a variable is numeric or not, if just tells if there's a digit in there. I wouldn't consider "d42d" numeric. Change the test to this: if [ -z $(echo $var | grep "^[0-9]\+$") ]; then echo "NON NUMERIC"; fi Now, it will return "NON NUMERIC" for things like "d42", "4d2", "42d"
flatcap · 519 weeks and 6 days ago
Ah, sorry, I have it mislabeled. It should be "execute a block of code only if $var is NON-numeric." However, flatcap, I also like your code too, perhaps it is more useful; I was just performing a bunch of ops on my computer that needed to determine if a number was purely non-numeric and included what I used.
AnusJenkins · 519 weeks and 5 days ago
If you don't need a block, that is a good way: ( echo $var | grep -q '[^0-9]' ) && echo "NON NUMERIC" ...and the -q makes a better clean output.
aurium · 519 weeks and 5 days ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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