linux - When does a variable add $ in bash -


i'm learning bash , confused when variable add $. find code like:

i=1 while [ $i -le 10 ] echo "$n * $i = `expr $i \* $n`" i=`expr $i + 1` done

the $ substitutes variable. writing $i insert value of i, no matter write it.

if want assign variable, makes no sense.


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