菜鸟学shell

Question

各位好，我是刚刚开始学shell编程，问题对你们来说很简单，哪位好心，帮我解决这个问题，多谢了。

#! /bin/sh
#whilecount
counter=0
while [ "$counter" -lt "5" ]
do
counter='expr $counter + 1'
echo $counter
done
echo "$counter is ge 5"

执行后报expr $coun + 1: integer expression expected
counter='expr $counter + 1'这样赋值有什么不对

Answer 1

1. counter=`expr $counter + 1`

复制代码

Answer 2

回复 1# islla

#!/bin/bash
counter=0
counter=$(( $counter+1 ))
echo "counter: $counter"

cou=0
cou=cou+1
echo "cou: $cou"

declare -i a=0
a=a+1
echo "a: $a"

declare -i b=0
b=b+1
echo "b: $b"

运行结果如下：
counter: 1
cou: cou+1
a: 1
b: 1

貌似你那样赋值不对哟，偶也是菜鸟，才学两天~