# variables.
## declare.
### plain.
inside functions you can declare functions like this:
```bash
variable1="hello"       # global variable.
local variable2="world" # local variable.
```
it is preferable to declare variables as `local` because this way they won't be left after the function execution.

### from output.
you can store another program's output into variable.
```bash
local jpegs=$(ls | grep .jpg$)
```

## use.
```bash
local myvar="boom!"
echo "this is it: ${myvar}" # better way.
echo "this is it: $myvar"   # simplified way.
```
you almost always want to wrap string variables in double quotes when reading their values. if you don't wrap them like `"$var1"` their content is not escaped and thus interpreted as a part of the function itself. you usually don't wrap them if you pass variable content "as is" to the command arguments i.e. if you want to preserve all flags and special characters like that:
```bash
local arguments=-n foo -i bar
myprogramm $arguments
```