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
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&/'
其他回答
虽然不是我要求的，但很有帮助
declare -u foo #When the variable is assigned a value, all lower-case characters are converted to upper-case.
foo=bar
echo $foo
BAR
反之亦然
declare -l foo #When the variable is assigned a value, all upper-case characters are converted to lower-case.
foo=BAR
echo $foo
bar
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 $str
}
first-letter-to-lower-xc () { v首字母到下| xclip -选择剪贴板 ｝
使用sed的一种方法:
echo "$(echo "$foo" | sed 's/.*/\u&/')"
打印:
Bar
据我所知，这是POSIX sh兼容的。
upper_first.sh:
#!/bin/sh
printf "$1" | cut -c1 -z | tr -d '\0' | tr [:lower:] [:upper:]
printf "$1" | cut -c2-
Cut -c1 -z以\0而不是\n结束第一个字符串。它被tr -d '\0'删除。它也可以省略-z并使用tr -d '\n'来代替，但如果字符串的第一个字符是换行符，则会中断。
用法:
$ upper_first.sh foo
Foo
$
在函数中:
#!/bin/sh
function upper_first ()
{
printf "$1" | cut -c1 -z | tr -d '\0' | tr [:lower:] [:upper:]
printf "$1" | cut -c2-
}
old="foo"
new="$(upper_first "$old")"
echo "$new"
仅使用awk
foo="uNcapItalizedstrIng"
echo $foo | awk '{print toupper(substr($0,0,1))tolower(substr($0,2))}'
