在字符串中填充零 [英] Padding zeros in a string

问题描述

我正在编写bash脚本以获取一些播客.问题在于某些播客数字是一位数字，而其他的是2/3位数字，因此我需要对它们进行填充以使其全部变为3位数字.

I'm writing a bash script to get some podcasts. The problem is that some of the podcast numbers are one digits while others are two/three digits, therefore I need to pad them to make them all 3 digits.

我尝试了以下操作:

n=1

n = printf %03d $n

wget http://aolradio.podcast.aol.com/sn/SN-$n.mp3

，但是变量'n'不会永久填充.我如何使其永久?

but the variable 'n' doesn't stay padded permanently. How can I make it permanent?

推荐答案

使用反引号指定printf命令(``)的结果:

Use backticks to assign the result of the printf command (``):

n=1
wget http://aolradio.podcast.aol.com/sn/SN-`printf %03d $n`.mp3

请注意，我删除了实际上并不必要的一行. 如果要将'printf％...'的输出分配给n，则可以 使用

Note that i removed one line which was not really necessary. If you want to assign the output of 'printf %...' to n, you could use

n=`printf %03d $n`

然后，使用之前使用的$ n变量替换.

and after that, use the $n variable substitution you used before.

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