shell if else 用法 syntax error near unexpected token `then'

1. 错误

#!/bin/bash

platform=$1

if[ "$platform" = "ibmaix64" ]

then

echo "$platform"

else

echo "hello ooo"

fi

Error ： syntax error near unexpected token `then'

原因： 条件语句 [ 符号的两边都要留空格

if [ $platform = "winx64" ]-----------------------right 绿色标记为空格

if[ $platform = "winx64" ]-----------------------wrong

if [$platform = "winx64" ]-----------------------wrong

2. 总结

2.1 空格

a.定义变量时, =号的两边不可以留空格

b.if语句 [ 符号的两边都要留空格

c.字符串比较, =两边要留空格

d. if 和then 在同一行 要加；

2.2 if 语句

#!/bin/sh

a=10

b=20

if [ $a == $b ]

then

echo "a is equal to b"

fi

#!/bin/sh

a=10

b=20

if [ $a == $b ]

then

echo "a is equal to b"

else

echo "a is not equal to b"

fi

#!/bin/sh

a=10

b=20

if [ $a == $b ]

then

echo "a is equal to b"

elif [ $a -gt $b ]

then

echo "a is greater than b"

elif [ $a -lt $b ]

then

echo "a is less than b"

else

echo "None of the condition met"

fi