在Bash中串联变量 [英] Concatenating variables in Bash
问题描述
毫无疑问,这是愚蠢的问题,我正在尝试将变量添加到变量的中间,因此例如在PHP中,我会这样做:
stupid question no doubt, I'm trying to add a variable to the middle of a variable, so for instance in PHP i would do this:
$mystring = $arg1 . '12' . $arg2 . 'endoffile';
所以输出可能是 20121201endoffile
,如何在linux bash脚本中实现相同的效果?
so the output might be 20121201endoffile
, how can I achieve the same in a linux bash script?
推荐答案
尝试执行此操作,在bash中没有要连接的特殊字符:
Try doing this, there's no special character to concatenate in bash :
mystring="${arg1}12${arg2}endoffile"
解释
如果不放在方括号中,您将问bash连接以下示例中的 $ arg112 + $ argendoffile
(我想这不是您要的内容):
explanations
If you don't put brackets, you will ask bash to concatenate $arg112 + $argendoffile
(I guess that's not what you asked) like in the following example :
mystring="$arg112$arg2endoffile"
在需要时,变量的括号是定界符.不需要时,可以使用它.
The brackets are delimiters for the variables when needed. When not needed, you can use it or not.
另一种解决方案
(便携式性较差:需要 bash
> 3.1)
another solution
(less portable : requirebash
> 3.1)
$ arg1=foo
$ arg2=bar
$ mystring="$arg1"
$ mystring+="12"
$ mystring+="$arg2"
$ mystring+="endoffile"
$ echo "$mystring"
foo12barendoffile
请参见 http://mywiki.wooledge.org/BashFAQ/013
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