If you want to print a non-space character right after the variable, use **curly brackets {}**
```bash
MANUFACTURER="Apple"
echo "I have a ${MANUFACTURER}'s mobile phone."
```
If you need to include **output from the command**, use **standard brackets ()**
```bash
echo "System stats: $(w | head -n1)"
```
Standard brackets cannot be used for regular variable, because shell tries to execute the command you put into a brackets.
```bash
echo "Test: $(MANUFACTURER)"
bash: command not found: MANUFACTURER
Test:
echo "Test: ${MANUFACTURER}"
Test: Apple
```