Numeric Check

[vodkadrinker]

Quick question on a numeric check in an if statement.

The user can input any number

if [ $numberinputbyuser = number ] ; then

do
whatever...

 

[columb]

The '=' sign is string comparison. What you want is one of

if [ $numberinputbyuser -eq $testnumber ]
then
  do something
fi

or, if you're creating a menu, for example

case $numberinputbyuser in
  1) do option 1;;
  2) do option 2;;
  3) do option 3;;
  *  do unknown option;;
esac

but we're back to string equality. i.e. if the user inputs '01' it won't match option 1

On the internet no one knows you're a dog

Columb Healy

 

[vodkadrinker]

I guess I could do a case statement to check for a numeric I was just wondering if there was an easy if statement just to see if an input was numeric or not.

case $numberinputbyuser in
[1-9]" "[1-9]|[1-9]" "[1-9][0-9]|[1-9]" "[1-9][0-9][0-9]|[1-9][0-9]" "[1-9][0-9]|[1-9][0-9]" "[1-9][0-9][0-9]|[1-9][0-9][0-9]" "[1-9][0-9][0-9])
do whatever...
;;
*)
do whatever...
;;
esac

 

[vodkadrinker]

or something more for my original question.

case $numberinputbyuser in
[1-9]|[1-9][0-9]|[1-9][0-9][0-9])
do whatever...
;;
*)
do whatever...
;;
esac

 

[PHV]

In ksh you may use typeset -i to force a variable to be numeric.

Hope This Helps, PH.
FAQ219-2884
FAQ181-2886

 

[columb]

Sorry, misunderstood your question
Something like

expr "$numberinputbyuser" : "[0-9]*$" > /dev/null && echo $numberinputbyuser is numeric

On the internet no one knows you're a dog

Columb Healy

 

[Mike042]

How about something like:

if [[ "$numberinputbyuser" = ?([+-])+([0-9]) ]]
then
do whatever for numbers (optionally signed integers) input ....
fi

Tested in Korn Shell on Solaris.

I hope that helps.

Mike