在bash中从字符串中删除所有特殊字符和大小写

I am writing a bash script that needs to parse filenames.

我正在编写一个需要解析文件名的bash脚本。

It will need to remove all special characters (including space): "!?.-_ and change all uppercase letters to lowercase. Something like this:

它需要删除所有特殊字符(包括空格):“!”-_并将所有大写字母改为小写字母。是这样的:

Some_randoM data1-A
More Data0

to:

somerandomdata1a
moredata0

I have seen lots of questions to do this in many different programming languages, but not in bash. Is there a good way to do this?

我在许多不同的编程语言中看到过很多这样的问题，但在bash中却没有。有什么好办法吗?

4 个解决方案

#1

cat yourfile.txt | tr -dc '[:alnum:]\n\r' | tr '[:upper:]' '[:lower:]'

The first tr deletes special characters. d means delete, c means complement (invert the character set). So, -dc means delete all characters except those specified. The \n and \r are included to preserve linux or windows style newlines, which I assume you want.

第一个tr删除特殊字符。d表示删除，c表示补码(反转字符集)。所以-dc表示删除除指定字符外的所有字符。\n和\r是用来保存linux或windows风格的换行符，我想您会喜欢的。

The second one translates uppercase characters to lowercase.

第二个将大写字母转换为小写字母。

#2

Pure bash solution:

纯bash的解决方案:

$ filename='Some_randoM data1-A'
$ f=${filename//[^[:alnum:]]/}
$ echo "$f"
SomerandoMdata1A
$ echo "${f,,}"
somerandomdata1a

A function for this:

一个函数:

clean() {
    local a=${1//[^[:alnum:]]/}
    echo "${a,,}"
}

Try it:

试一试:

$ clean "More Data0"
moredata0

#3

if you are using mkelement0 and Dan Bliss approach. You can also look into sed + POSIX regular expression.

如果你使用mkelement0和Dan Bliss方法。您还可以查看sed + POSIX正则表达式。

cat yourfile.txt | sed 's/[^a-zA-Z0-9]//g'

Sed matches all other characters that are not contained within the brackets except letters and numbers and remove them.

Sed匹配除字母和数字之外不在括号内的所有其他字符，并删除它们。

#4

I've used tr to remove any characters that are not part of [:print:] class

我使用tr来删除不属于[:print:]类的任何字符

cat file.txt | tr -dc '[:print:]'

或

echo "..." | tr -dc '[:print:]'

Additionally you might want to | (pipe) the output to od -c to confirm the result

此外，您可能希望|(管道)输出到od -c以确认结果

cat file.txt | tr -dc '[:print:]' | od -c

#1

cat yourfile.txt | tr -dc '[:alnum:]\n\r' | tr '[:upper:]' '[:lower:]'