Expr and Test

expr Can be used to perform simple math expressions (plus other stuff)

test Can be used to evaluate logical expressions (plus other stuff)

Abbreviate with []'s

Numeric logical operators include String operators include

-le, -ge, -lt, -gt, -eq, -ne =, !=

e.g.

a=1

gonzo_1="hello"

gonzo_2="there"

while [ $a -le 10 ]; do

/bin/echo "[$a]\c"

eval gonzo_value=\$gonzo_$a

if [ $a -eq 3 ]; then

eval gonzo_$a=1

if [ "$gonzo_value" != "" ]; then

/bin/echo "$gonzo_value \c"

a=`expr $a + 1`

done

--> [1]hello [2]there [3]1 [4][5][6][7][8][9][10]