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only a number can be entered no letters?

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# 1  
Old 11-29-2011
only a number can be entered no letters?
ok the user can only enter a number if a letter is entered it shouldnt be accepted
This is what i have so far

Code:
read -p "How many cars to enter:" cars
until [ "$cars" -ge 1 -a "$cars" -ne [A-Za-z]
do
read -p "Invalid number. Please re-enter:" $tags
done

# 2  
Old 11-29-2011
-ne doesn't work that way.

What you can do depends on what system and shell you have.

What's your system?

What's your shell?
# 3  
Old 11-29-2011
You can use grep and test the return of it ($?)

For instance :
Code:
read NUM
echo $NUM | grep "[a-zA-Z]"
if [ $? -eq 1 ]; then
printf "number \n"
else
printf "not a number \n"
fi

Hope that helps.
Regards
Peasant.
# 4  
Old 11-29-2011
That repeats it back to the screen, does many unnecessary things, and will return false results for strings which have characters like ! @ # $ % ^ & * ( ) _ = + .

How to do it depends on what system you have and what your shell is.

What's your system?

What's your shell?
# 5  
Old 11-29-2011
Haven't we been here before with gangsta?
https://www.unix.com/shell-programmin...ng-number.html
We left the last thread with an error on line 52 of a 3-line script.
In addition to posting the Operating Systems and version and Shell , please post the actual script and explain what you are trying to do.
# 6  
Old 11-29-2011
There's also a good answer from cfajohnson to a quite similar question here:

https://www.unix.com/shell-programmin...g-command.html

Closing this thread.
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