在 bash 脚本中使用 expr substr 语法错误
我编写了一个小型 bash 脚本来尝试获取字符串的最后 x 个字符。
#!/bin/bash
string="This is my string. I want THIS TEXT"
echo -e "string: $string"
length=${#string}
echo "length: $length"
start=$(($length-9))
echo "start: $start"
text=`expr substr $string $start 9`
echo "text: $text"
exit 0
输出给了我一个“语法错误”：
string: This is my string. I want THIS TEXT
length: 35
start: 26
expr: syntax error
text:
我确信它相当简单，但我无法弄清楚。有人能指出我做错了什么吗？这是在 SunOS 上运行的。
I have written small bash script to try to get the last x characters of a string.
#!/bin/bash
string="This is my string. I want THIS TEXT"
echo -e "string: $string"
length=${#string}
echo "length: $length"
start=$(($length-9))
echo "start: $start"
text=`expr substr $string $start 9`
echo "text: $text"
exit 0
The output is giving me a "syntax error":
string: This is my string. I want THIS TEXT
length: 35
start: 26
expr: syntax error
text:
I'm sure it's fairly simple but I can't figure it out. Can anybody point out what I'm doing wrong? This is being run on SunOS.
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这个怎么样？
其中 -4 是距末尾的偏移量
how about this?
where -4 is your offset from the end