How would one go about comparing a variable, lets say
Var1
to a range of numbers such as 0-5. If Var1 is in that range then the statement will return true, else will print an error or exit.
3
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How are you being given this range?Ignacio Vazquez-Abrams– Ignacio Vazquez-Abrams2014-03-23 19:37:51 +00:00Commented Mar 23, 2014 at 19:37
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Var1 will be given through stdin, basically if the user doesnt input 1,2,3,4 or 5 through stdin then it will just print an erroruser2860658– user28606582014-03-23 19:41:43 +00:00Commented Mar 23, 2014 at 19:41
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So just test if it's greater than 0 and less than 6?Reinstate Monica Please– Reinstate Monica Please2014-03-23 19:43:51 +00:00Commented Mar 23, 2014 at 19:43
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1 Answer
In simple terms, you can just test the variable passed while running the script:
#!/bin/bash
if (( 0 <= $1 && $1 <= 5 )); then
echo "In range"
else
echo "Not in range"
fi
Pass the number to the script and it will test it against your range. For example, if the above it put in a script called check.sh then:
$ bash check.sh 10
Not in range
$ bash check.sh 3
In range
You can make the script executable to avoid using bash ... whenever you need to run the script. The $1 used above the is the first parameter passed to the script. If you don't like to use positional variables, then you can save it a variable inside the script if you wish.
2 Comments
glenn jackman
+1. Purely as a matter of style, I write
(( 0 <= $1 && $1 <= 5 )) -- that's closest to math notation a ≤ x ≤ b
jaypal singh
Thanks @glennjackman. Actually, I like that style. Will use that from now on. Makes it more readable too. Thank you. Will update.