$ (Dollar sign prefix to a variable)

‘$variable’ The dollar sign prefix allows the shell to interpret the phrase as a variable.

$ echo $PATH
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games

Useful Options / Examples

‘VARX=”5”; echo $VARX’

$ VARX=5; echo $VARX
5

Break it down

• The variable VARX has the value 5, and in order to print this value, $ must be used.

‘EXEC=”./hello.out”; $EXEC’

$ EXEC="./hello.out"; $EXEC
Hello World!

Break it down

• The terminal replaces the $EXEC with its value, and reads it as if it was typed by the user. Therefore, the terminal runs the executable ‘hello.out’.