正则表达式替换可选的下划线

Question

如果下划线存在，我需要删除它。

string VIEW VXABC expected result VIEW ABC
string VIEW V_XABC expected result VIEW ABC

这是我的尝试，但我不知道结果

echo "VIEW VXABC" |sed 's/VIEW V_?X/VIEW ABC/'
VIEW VXABC

Answer 1

[me@home]$ echo VIEW V_XABC | sed -r 's/VIEW V_?X/VIEW /' 
VIEW ABC
[me@home]$ echo VIEW VXABC | sed -r 's/VIEW V_?X/VIEW /' 
VIEW ABC

注意 -r 选项。来自man page :

-r, --regexp-extended
    use extended regular expressions in the script.