how can i grep number in a file

if i want to grep 1234
can i use?

read inp1 inp2
echo inp1 > inp1.txt ;echo inp2 > inp2.txt
if inp=`grep -w [0-9] inp1.txt` -o inp1=`grep -w [0-9] inp2.txt`


thanks

You can directly grep the number.
If you want to grep any 4 digit number, you can use

i know what you mean
but the problem is i do not know what the user will input
the user may input anything and i need to check if the input is number . else the error should be display

As I know, there is no straight forward numeric check in shell script.
Through logic you can do.
--
typeset -i num
echo "Please enter string :"
read str
num=`expr $str + 1 2>/dev/null`
if [ $? -eq 0 ]
then
echo "Entered string is a number $str"
else
echo "Entered string is not a number $str"
fi
--
Hope it will help
Thanks
Sumit

hi,

is there any simpler code using grep command to test whether input is number or not?

thanks

Be sure to add an extra check whether the user has given 0 as input when using sumitc's suggestion, which is the far better way to accomplish what you really want.

Generally one could render your idea in a more elegant way as follows

hi,
that does work but it doesnot support input more than one digit
if i want to enter number with 2 digits, the command does not work,
what should i alter to allow the code to read input of more than one digit?
thanks