bash中有没有将字符串转换为小写字符串的方法?
例如,如果我有:
a="Hi all"
我想将其转换为:
"hi all"
bash中有没有将字符串转换为小写字符串的方法?
例如,如果我有:
a="Hi all"
我想将其转换为:
"hi all"
当前回答
在Bash 4中:
小写
$ string="A FEW WORDS"
$ echo "${string,}"
a FEW WORDS
$ echo "${string,,}"
a few words
$ echo "${string,,[AEIUO]}"
a FeW WoRDS
$ string="A Few Words"
$ declare -l string
$ string=$string; echo "$string"
a few words
大写
$ string="a few words"
$ echo "${string^}"
A few words
$ echo "${string^^}"
A FEW WORDS
$ echo "${string^^[aeiou]}"
A fEw wOrds
$ string="A Few Words"
$ declare -u string
$ string=$string; echo "$string"
A FEW WORDS
切换(未记录,但可在编译时配置)
$ string="A Few Words"
$ echo "${string~~}"
a fEW wORDS
$ string="A FEW WORDS"
$ echo "${string~}"
a FEW WORDS
$ string="a few words"
$ echo "${string~}"
A few words
大写(未记录,但可在编译时配置)
$ string="a few words"
$ declare -c string
$ string=$string
$ echo "$string"
A few words
标题大小写:
$ string="a few words"
$ string=($string)
$ string="${string[@]^}"
$ echo "$string"
A Few Words
$ declare -c string
$ string=(a few words)
$ echo "${string[@]}"
A Few Words
$ string="a FeW WOrdS"
$ string=${string,,}
$ string=${string~}
$ echo "$string"
A few words
要关闭声明属性,请使用+。例如,声明+c字符串。这会影响后续赋值,而不是当前值。
declare选项更改变量的属性,但不更改内容。示例中的重新分配会更新内容以显示更改。
编辑:
按照ghostdog74的建议,添加了“按单词切换第一个字符”(${var~})。
编辑:更正波浪号行为以匹配Bash 4.3。
其他回答
在bash 4中,可以使用类型集
例子:
A="HELLO WORLD"
typeset -l A=$A
tr:
a="$(tr [A-Z] [a-z] <<< "$a")"
AWK:
{ print tolower($0) }
sed:
y/ABCDEFGHIJKLMNOPQRSTUVWXYZ/abcdefghijklmnopqrstuvwxyz/
在Bash 4中:
小写
$ string="A FEW WORDS"
$ echo "${string,}"
a FEW WORDS
$ echo "${string,,}"
a few words
$ echo "${string,,[AEIUO]}"
a FeW WoRDS
$ string="A Few Words"
$ declare -l string
$ string=$string; echo "$string"
a few words
大写
$ string="a few words"
$ echo "${string^}"
A few words
$ echo "${string^^}"
A FEW WORDS
$ echo "${string^^[aeiou]}"
A fEw wOrds
$ string="A Few Words"
$ declare -u string
$ string=$string; echo "$string"
A FEW WORDS
切换(未记录,但可在编译时配置)
$ string="A Few Words"
$ echo "${string~~}"
a fEW wORDS
$ string="A FEW WORDS"
$ echo "${string~}"
a FEW WORDS
$ string="a few words"
$ echo "${string~}"
A few words
大写(未记录,但可在编译时配置)
$ string="a few words"
$ declare -c string
$ string=$string
$ echo "$string"
A few words
标题大小写:
$ string="a few words"
$ string=($string)
$ string="${string[@]^}"
$ echo "$string"
A Few Words
$ declare -c string
$ string=(a few words)
$ echo "${string[@]}"
A Few Words
$ string="a FeW WOrdS"
$ string=${string,,}
$ string=${string~}
$ echo "$string"
A few words
要关闭声明属性,请使用+。例如,声明+c字符串。这会影响后续赋值,而不是当前值。
declare选项更改变量的属性,但不更改内容。示例中的重新分配会更新内容以显示更改。
编辑:
按照ghostdog74的建议,添加了“按单词切换第一个字符”(${var~})。
编辑:更正波浪号行为以匹配Bash 4.3。
仅对字母表进行大小写转换。所以,这应该很有效。
我专注于将a-z之间的字母从大写转换为小写。任何其他字符都应按原样打印在标准输出中。。。
将a-z范围内的path/to/file/filename中的所有文本转换为a-z
用于将小写转换为大写
cat path/to/file/filename | tr 'a-z' 'A-Z'
用于从大写转换为小写
cat path/to/file/filename | tr 'A-Z' 'a-z'
例如
文件名:
my name is xyz
转换为:
MY NAME IS XYZ
示例2:
echo "my name is 123 karthik" | tr 'a-z' 'A-Z'
# Output:
# MY NAME IS 123 KARTHIK
示例3:
echo "my name is 123 &&^&& #@$#@%%& kAR2~thik" | tr 'a-z' 'A-Z'
# Output:
# MY NAME IS 123 &&^&& #@0@%%& KAR2~THIK
尽管这个问题有多古老,而且与技术龙的答案相似。我很难找到一个能够跨大多数平台(我使用的平台)以及旧版本bash移植的解决方案。我还对数组、函数以及使用prints、echo和临时文件来检索琐碎变量感到失望。到目前为止,这对我来说非常有效,我想我会分享。我的主要测试环境是:
GNUbash,版本4.1.2(1)-发布(x86_64-redhat-linux-GNU)GNUbash,版本3.2.57(1)-发布(sparc-sun-solaris2.10)
lcs="abcdefghijklmnopqrstuvwxyz"
ucs="ABCDEFGHIJKLMNOPQRSTUVWXYZ"
input="Change Me To All Capitals"
for (( i=0; i<"${#input}"; i++ )) ; do :
for (( j=0; j<"${#lcs}"; j++ )) ; do :
if [[ "${input:$i:1}" == "${lcs:$j:1}" ]] ; then
input="${input/${input:$i:1}/${ucs:$j:1}}"
fi
done
done
循环的简单C样式,用于遍历字符串。如果您以前没有看到过类似的内容,请选择下面的行这是我学到的。在这种情况下,该行检查输入中是否存在字符${input:$i:1}(小写),如果存在,则用给定的字符${ucs:$j:1}(大写)替换它,并将其存储回输入中。
input="${input/${input:$i:1}/${ucs:$j:1}}"