Multiplication on command line terminal

Question

I\'m using a serial terminal to provide input into our lab experiment. I found that using

$ echo \"5X5\"

just returns a string of \"

Answer 1

Internal Methods

Bash supports arithmetic expansion with $(( expression )). For example:

$ echo $(( 5 * 5 ))
25

External Methods

A number of utilities provide arithmetic, including bc and expr.

$ echo '5 * 5' | /usr/bin/bc
25

$ /usr/bin/expr 5 \* 5
25