Bash 脚本，如何删除尾随子字符串，不区分大小写？
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Bash scripting, how to remove trailing substring, case insensitive?
提问by basher1
I am modifying a script that reads in a user email. It is very simple, too simple.
我正在修改一个读取用户电子邮件的脚本。这很简单，太简单了。
echo -n "Please enter your example.com email address: "
read email
email=${email%%@example.com} # removes trailing @example.com from email
echo "email is $email"
This works, but only for lower case @example.com. How could I modify this to remove the trailing @example.com, case insensitive?
这有效，但仅适用于小写@example.com。我如何修改它以删除尾随的@example.com，不区分大小写？
采纳答案by kanaka
If you have bash 4:
如果你有 bash 4：
email=${email,,}
email=${email%%@example.com}
Otherwise, perhaps just use tr:
否则，也许只需使用 tr：
email=$(echo "${email}" | tr "A-Z" "a-z")
email=${email%%@example.com}
Update:
更新：
If you are just wanting to strip the host (any host) then perhaps this is really what you want:
如果您只是想剥离主机（任何主机），那么这可能就是您真正想要的：
email=${email%%@*}
回答by Paused until further notice.
For Bash 3.2 and greater:
对于 Bash 3.2 及更高版本：
shopt -s nocasematch
email='[email protected]'
pattern='^(.*)@example.com$'
[[ $email =~ $pattern ]]
email=${BASH_REMATCH[1]} # result: JoHnDoE
回答by thkala
How about using sed?
使用sed怎么样？
email="$(sed 's|@example\.com$||i' <<<"$email")"
Note the 'i' flag in the sed substitution command which requests case-insensitive matching.
请注意 sed 替换命令中的“i”标志，该命令要求不区分大小写的匹配。
回答by carlo
Here's yet another (though a bit lengthy) take on it:
这是另一个（虽然有点冗长）的看法：
email='[email protected]'
email=${email%%@[Ee][Xx][Aa][Mm][Pp][Ll][Ee].[Cc][Oo][Mm]}
echo "email is $email"
回答by feklee
Use case insensitive matching to a regular expression:
使用不区分大小写的正则表达式匹配：
echo -n "Please enter your example.com email address: "
read email
shopt -s nocasematch # Makes comparisons case insensitive
if [[ $email =~ example.com$ ]]; then
domain=${BASH_REMATCH[0]}
echo "email is ${email%%@$domain}"
fi
Alternatively, you can cut off a string based on its length (which only makes sense if you know that the user entered the domain correctly):
或者，您可以根据字符串的长度截断字符串（这仅在您知道用户正确输入域时才有意义）：
echo -n "Please enter your example.com email address: "
read email
domain=example.com
email_length=${#email}
domain_length=${#domain}
name_length=$(($email_length-$domain_length-1))
email=${email:0:$name_length} # removes trailing @example.com from email
echo "email is $email"
回答by Hsin
echo -n "Please enter your example.com email address: "
read _email
_email=$(echo $_email | awk 'BEGIN{ FS="@" } {print }')
echo $_email
and for transfer email to lower case you can use declare, such as
并将电子邮件传输到小写，您可以使用声明，例如
declare -l email=$email
声明 -l email=$email
