Linux 如何在bash中提取子字符串
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how to extract a substring in bash
提问by MOHAMED
I have the following string in bash with length > 4
我在bash中有以下字符串，长度> 4
str = "abcdefghijklmno"
and I want to extract into str2the 5 first charachter of str. So
我想提取到 . 的str2第 5 个字符中str。所以
str2="abcde"
How to do it with bash?
如何用 bash 做到这一点？
采纳答案by fedorqui 'SO stop harming'
Do use the expression
使用表达式
{string:position:length}
So in this case:
所以在这种情况下：
$ str="abcdefghijklm"
$ echo "${str:0:5}"
abcde
See other usages:
查看其他用法：
$ echo "${str:0}" # default: start from the 0th position
abcdefghijklm
$ echo "${str:1:5}" # start from the 1th and get 5 characters
bcdef
$ echo "${str:10:1}" # start from 10th just one character
k
$ echo "${str:5}" # start from 5th until the end
fghijklm
Taken from:
- wooledge.org - How can I use parameter expansion? How can I get substrings? How can I get a file without its extension, or get just a file's extension?
- Shell Command Language - 2.6.2 Parameter Expansion
来自
- wooledge.org -我如何使用参数扩展？我怎样才能得到子字符串？如何获取没有扩展名的文件，或者只获取文件的扩展名？
- Shell 命令语言 - 2.6.2 参数扩展
