我想用bash将字符串中的第一个字符大写。
foo="bar";
//uppercase first character
echo $foo;
应打印“Bar”;
我想用bash将字符串中的第一个字符大写。
foo="bar";
//uppercase first character
echo $foo;
应打印“Bar”;
当前回答
Posix兼容,子进程更少:
v="foo[Bar]"
printf "%s" "${v%"${v#?}"}" | tr '[:lower:]' '[:upper:]' && printf "%s" "${v#?}"
==> Foo[Bar]
其他回答
这里只是为了好玩:
foo="bar";
echo $foo | awk '{$1=toupper(substr($1,0,1))substr($1,2)}1'
# or
echo ${foo^}
# or
echo $foo | head -c 1 | tr [a-z] [A-Z]; echo $foo | tail -c +2
# or
echo ${foo:1} | sed -e 's/^./\B&/'
下面是“原生”文本工具的使用方法:
#!/bin/bash
string="abcd"
first=`echo $string|cut -c1|tr [a-z] [A-Z]`
second=`echo $string|cut -c2-`
echo $first$second
first-letter-to-lower () {
str=""
space=" "
for i in $@
do
if [ -z $(echo $i | grep "the\|of\|with" ) ]
then
str=$str"$(echo ${i:0:1} | tr '[A-Z]' '[a-z]')${i:1}$space"
else
str=$str${i}$space
fi
done
echo $str
}
first-letter-to-upper-xc () {
v-first-letter-to-upper | xclip -selection clipboard
}
first-letter-to-upper () {
str=""
space=" "
for i in $@
do
if [ -z $(echo $i | grep "the\|of\|with" ) ]
then
str=$str"$(echo ${i:0:1} | tr '[a-z]' '[A-Z]')${i:1}$space"
else
str=$str${i}$space
fi
done
echo $str
}
first-letter-to-lower-xc () { v首字母到下| xclip -选择剪贴板 }
如果第一个字符不是字母(而是制表符、空格和转义双引号)怎么办?我们最好测试它,直到我们找到一个字母!所以:
S=' \"ó foo bar\"'
N=0
until [[ ${S:$N:1} =~ [[:alpha:]] ]]; do N=$[$N+1]; done
#F=`echo ${S:$N:1} | tr [:lower:] [:upper:]`
#F=`echo ${S:$N:1} | sed -E -e 's/./\u&/'` #other option
F=`echo ${S:$N:1}
F=`echo ${F} #pure Bash solution to "upper"
echo "$F"${S:(($N+1))} #without garbage
echo '='${S:0:(($N))}"$F"${S:(($N+1))}'=' #garbage preserved
Foo bar
= \"Foo bar=
只大写第一个单词:
foo='one two three'
foo="${foo^}"
echo $foo
一二三
将变量中的每个单词大写:
foo="one two three"
foo=( $foo ) # without quotes
foo="${foo[@]^}"
echo $foo
一二三
(适用于bash 4+)