Check for Intigers

[ojosVerdes]

How do I check if the argument passed to a script is an interger?

I am using bourne shell.

Thanks in advance

 

[olded]

Hi:

Check this thread:

thread822-382650

The thread is on functions, but there's 3 different ways used to check whether an argument is integer. Once should work for you.

Regards,

Ed

 

[jamisar]

a simple way

case x$1 in x) #nothing entered
;; x[0-9]*[0-9]) #integer entered
;; *) #something else entered
;; esac -----------
when they don't ask you anymore, where they are come from, and they don't tell you anymore, where they go ... you'r getting older !

 

[ojosVerdes]

Jamisar,
This is the code I have and I embedded you code in but is not working as expected.

What Am I doing wrong?

Thanks in advance.


#!/bin/sh
num=$#
[ $# -ne 2 ] && { echo "Usage: $0 Integer1 Integer2"; exit;}
x=0
while test $x -lt $num
x=`expr $x + 1`
do
case x$x in x)#nothing entered
;; x[0-9]*[0-9]) echo Integer $#
;; *) echo Something Else.
;; esac
done

 

[jamisar]

i don't see why
try a workaround.... why so complex???


checkinput()
{
case $1 in [0-9]|[0-9]*[0-9]) return 0 ;; esac
return 1
}

exitusage()
{
echo "Usage: $0 Integer1 Integer2"
exit
}

[ $# -ne 2 ] && exitusage
checkinput $1 || exitusage && A=$1
checkinput $2 || exitusage && B=$2

-----------
when they don't ask you anymore, where they are come from, and they don't tell you anymore, where they go ... you'r getting older !

 

[ojosVerdes]

Jamisar,
Thanks for taking your time. I am a novice user and I was not really aware of fuctions. perhaps I will find out more about them.

Yes your way works good except when you enter 2.5 or 5.2. It lets those numbers go through. I only want integers and they can be like -56 or just plain 45. positive integers dont need a sign.

Thanks again.

Ojos Verdes

 

[jamisar]

ojos verdes:
i fergot negativ
prepend a [\-] in the case statement
nota 5.3 is NOT an integer -----------
when they don't ask you anymore, where they are come from, and they don't tell you anymore, where they go ... you'r getting older !

 

[ojosVerdes]

Jamisar,
I want negative integers. for example the following should be valid:
Proj2 -5 2 #valid
Proj2 2 -8 #Valid
Invalids
Proj2 -5 .2 # invalid because the .2
proj2 1.5 6 #invalid because the 1.5

the part that is not working is the negative integers.
Thanks again

 

[jamisar]

sure you can write a c, perl or awk program, this just a shell ...

1.sed purge '-0'
2 sed purge '+'
3.sed purge .[0-9]*
this is fast, no computing just regexp.
NOTA the input 'qq77mm' is not checked for.
i personnaly prefer /bin/[bd]c.

checkinput()
{
eval $1=`/bin/echo $2|/bin/sed -e 's/-0/0/;s/+//' -ne 's/\([\-]\)*\([0-9][0-9]*\).*/\1\2/p'`
}

checkinput A $1 ; [ x$A = x ] && exitusage
checkinput B $2 ; [ x$B = x ] && exitusage -----------
when they don't ask you anymore, where they are come from, and they don't tell you anymore, where they go ... you'r getting older !

 

[jamisar]

this is the only practicable way without writing c, perl, awk and other

checkinput()
{
eval $1=`/bin/echo "a=$2;a*=10;scale=0;a/=10;a;quit" | /bin/bc 2>&1 | /bin/grep error >/dev/null` && return 1
return 0
}

checkinput A $1 || exitusage
checkinput B $2 || exitusage

...compute... in $A is the 1.param in $B the second. -----------
when they don't ask you anymore, where they are come from, and they don't tell you anymore, where they go ... you'r getting older !