expr

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expr

expr

expr is an older external command that evaluates a simple arithmetic or string expression and prints the result. It requires spaces around every operator and operand, unlike $(( )). Most modern scripts prefer $(( )) or let, but expr still appears in older scripts.

Warning: expr 1+1 (no spaces) prints 1+1 literally instead of 2 — spaces around operators are mandatory.

Example: expr

bash

#!/bin/bash
result=$(expr 5 + 3)
echo "5 + 3 = $result"

result=$(expr 10 \* 2)
echo "10 * 2 = $result"

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expr
for Loop Over a List
Arithmetic Expansion $(( ))
C-Style for Loop
let
while Loop
bc for Floating-Point Math
until Loop
Comparison Operators
break and continue
Increment and Decrement
Looping Over Array Elements
Math Functions
Looping Over Command Output

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expr

expr

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