bash 将搜索字符串作为 shell 变量传递给 grep
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passing search string to grep as a shell variable
提问by user1222073
I have to write a small bash script that determines if a string is valid for the bash variable naming rules. My script accepts the variable name as an argument. I am trying to pass that argument to the grep command with my regex but everything I tried, grep tries to open the value passed as a file.
我必须编写一个小的 bash 脚本来确定字符串对于 bash 变量命名规则是否有效。我的脚本接受变量名作为参数。我试图用我的正则表达式将该参数传递给 grep 命令，但我尝试过的一切，grep 尝试打开作为文件传递的值。
I tried placing it after the command as such
grep "$regex" ""
and also tried passing it as redirected input, both with and without quotes
grep "$regex" <""
and both times grep tries to open it as a file. Is there a way to pass a variable to the grep command?
并且两次 grep 都尝试将其作为文件打开。有没有办法将变量传递给 grep 命令？
回答by that other guy
Both your examples interpret "$1" as a filename. To use a string, you can use
您的两个示例都将 "$1" 解释为文件名。要使用字符串，您可以使用
echo "" | grep "$regex"
or a bash specific "here string"
或 bash 特定的“此处字符串”
grep "$regex" <<< ""
You can also do it faster without grep with
你也可以在没有 grep 的情况下更快地完成
[[ =~ $regex ]] # regex syntax may not be the same as grep's
or if you're just checking for a substring,
或者如果你只是检查一个子字符串，
[[ == *someword* ]]
回答by hek2mgl
You can use the bash builtin feature =~. Like this:
您可以使用 bash 内置功能=~。像这样：
if [[ "$string" =~ $regex ]] ; then
echo "match"
else
echo "dont match"
fi
