Using a command declare for arithmetic
Whenever we declare any variable, by default, this variable stores the string type of data. We cannot do arithmetic operations on them. We can declare a variable as an integer by using the declare command. Such variables are declared as integers; if we try to assign a string to them, then bash assigns 0 in these variables.
Bash will report an error if we try to assign fractional values (floating points) to integer variables.
We can create an integer variable called value, shown as follows:
$ declare –i value
We tell the shell that the variable value is of type integer. Otherwise, shell treats all variables as character strings:
If we try to assign the
namestring to the integer variablevalue, then thevaluevariable will be assigned the0value by Bash shell:$ value=name $ echo $value 0
We need to enclose numbers between double quotes, otherwise we should not use space in arithmetic expressions:
$ value=4 + 4 bash: +: command not found
When we remove...
