Mastering Linux Shell Scripting - Second Edition

Testing integers

As well as testing string values of bash scripts, we can test for integer values and whole numbers. Another way of testing the input of a script is to count the numbers of positional parameters and also test if the number is above 0:

test $# -gt 0 

Or using the brackets, as follows:

[ $# -gt 0 ] 

When in a relationship, the top positional parameters of the $# variable represent the number of parameters passed to the script.

There are many tests that can be done for numbers:

• number1 -eq number2: This checks if number1 is equal to number2
• number1 -ge number2: This checks if number1 is greater than or equal to number2.

• number1 -gt number2: This checks if number1 is greater than number2
• number1 -le number2: This checks if ...