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How do you subtract using the shell?
The following arithmetic operators are supported by Bourne Shell….Unix / Linux – Shell Arithmetic Operators Example.
| Operator | Description | Example |
|---|---|---|
| – (Subtraction) | Subtracts right hand operand from left hand operand | `expr $a – $b` will give -10 |
Which command is used to subtract two numbers?
To do simple subtraction, use the – (minus sign) arithmetic operator. For example, if you enter the formula =10-5 into a cell, the cell will display 5 as the result.
How to add or subtract two numbers with Bash?
You can assign from that; also note the $ operators on the variable names inside ( ()) are optional): In scripting $ ( ()) is preferable since it avoids a fork/execute for the expr command. The existing answer is pure bash, so it will be faster than this, but it can only handle integers.
How can I do Division with variables in a Linux shell?
The default shell on most Linux distributions is Bash. In Bash, variables must use a dollar sign prefix for parameter expansion. For example: Of course, Bash also has arithmetic operators and a special arithmetic expansion syntax, so there’s no need to invoke the expr binary as a separate process.
How to subtract two timestamps in bash script?
Note that the %N format specifier (nanoseconds) is a GNU extension and is not handled in the default macOS date command. Either (a) brew install coreutils and use gdate in the function above or (b) use this alternative function on macOS (but note it lacks support for sub-second measurements):
Can you use expr instead of Bash syntax?
Try this Bash syntax instead of trying to use an external program expr: But keep in mind using expr is going to be slower than the internal Bash syntax I provided above. White space is important, expr expects its operands and operators as separate arguments. You also have to capture the output.