如何在 Bash 中将大写字母转换为小写字母或相反？

发布于 2025-01-07 03:18:58 字数 559 浏览 1 评论 0原文

可能的重复：
在 bash shell 脚本中将字符串转换为小写 < /p>

对于例如：

 echo *****Language translator*****
 echo please choose the language
 for Chinese enter c
 for French enter f

以一种简单的方式，我希望能够识别中文的 C 和 c； f 和 F 也是如此，被识别为法语。

有没有办法将所有内容都转换为小写？

这里是部分代码：

if [ $language == c ];
那么
echo“输入要翻译的单词：”
读取单词到翻译

原文

Possible Duplicate:
converting string to lower case in bash shell scripting

For example:

 echo *****Language translator*****
 echo please choose the language
 for Chinese enter c
 for French enter f

In a simple way I want to be able to recognize both C and c for Chinese;
and the same thing for f and F, recognized as French.

Is there a way to convert everything to lower case?

Here part of the code:

if [ $language == c ];
then
echo "Enter the word to translate:"
read word_to_translate

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画中仙 2025-01-14 03:18:58

您可以使用 tr 将字符切换为小写/大写：

echo $language | tr '[A-Z]' '[a-z]'

You can use tr to switch the chars to lowercase/uppercase:

echo $language | tr '[A-Z]' '[a-z]'

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凉薄对峙 2025-01-14 03:18:58

您可以使用以下大小写修饰符（来自 man bash）：

${parameter^}      # Convert the first character in ${parameter} to uppercase
${parameter^^}     # Convert all characters in ${parameter} to uppercase
${parameter,}      # Convert the first character in ${parameter} to lowercase
${parameter,,}     # Convert all characters in ${parameter} to lowercase

因此您的代码可能如下所示：

# Read one character into $lang, with a nice prompt.
read -n 1 -p "Please enter c for Chinese, or f for French: " lang
if [ "${lang,,}" == "c" ]; then
  echo "Chinese"
elif [ "${lang,,}" == "f" ]; then
  echo "French"
else
  echo "I don't speak that language."
fi

You can use the following case-modifiers (from man bash):

${parameter^}      # Convert the first character in ${parameter} to uppercase
${parameter^^}     # Convert all characters in ${parameter} to uppercase
${parameter,}      # Convert the first character in ${parameter} to lowercase
${parameter,,}     # Convert all characters in ${parameter} to lowercase

So your code might look something like this:

# Read one character into $lang, with a nice prompt.
read -n 1 -p "Please enter c for Chinese, or f for French: " lang
if [ "${lang,,}" == "c" ]; then
  echo "Chinese"
elif [ "${lang,,}" == "f" ]; then
  echo "French"
else
  echo "I don't speak that language."
fi

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草莓酥 2025-01-14 03:18:58

现代版本的 tr 支持 POSIX 字符类 [:upper:] 和 [:lower:]

tr -s '[:upper:]'  '[:lower:]' < inputfile > outputfile

所有字符类都在这里：

http://ss64.com/bash/tr.html

Modern versions of tr have support for POSIX character classes [:upper:] and [:lower:]

tr -s '[:upper:]'  '[:lower:]' < inputfile > outputfile

All of the character classes are here:

http://ss64.com/bash/tr.html

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救赎№ 2025-01-14 03:18:58

我可能会使用 case 语句，尽管还有其他方法可以做到这一点：

read language
case "$language" in
([cC]) echo 'Chinese';;
([fF]) echo 'French';;
(*)    echo 'Unrecognized language abbreviation';;
esac

如果您需要开关外部的值，您可以在 case 中进行规范分配：

read language
case "$language" in
([cC]) lingua='zh_tw'; echo 'Chinese';;
([fF]) lingua='fr_fr'; echo 'French';;
(*)    echo 'Unrecognized language abbreviation';;
esac

I'd probably use a case statement, though there are other ways to do it:

read language
case "$language" in
([cC]) echo 'Chinese';;
([fF]) echo 'French';;
(*)    echo 'Unrecognized language abbreviation';;
esac

You could make a canonical assignment in the case if you need the values outside the switch:

read language
case "$language" in
([cC]) lingua='zh_tw'; echo 'Chinese';;
([fF]) lingua='fr_fr'; echo 'French';;
(*)    echo 'Unrecognized language abbreviation';;
esac

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